LIDAR Analyst 5.1 Tutorial

LIDAR Analyst Tutorial

5.1.X

LIDAR Analyst® 5.1.x for ArcGIS® Tutorial

Copyright Notice

© 2000-2013 Overwatch Systems, Ltd (Overwatch) All Rights Reserved Worldwide.

Trademarks

LIDAR Analyst® is a registered trademark of Overwatch Systems, Ltd., an operating unit of Textron Systems Corporation, a Textron Inc. (NYSE: TXT) company. We put the information in GIS is a service mark of Overwatch, ESRI, ArcGIS, ArcMap, ArcView, ArcScene, 3D Analyst and Spatial Analyst are trademarks, registered trademarks, or service marks of Environmental Systems Research Institute, Inc. Google Earth™ mapping service is a trademark of Google Inc. Windows® is a registered trademark of Microsoft Corporation in the United States and other countries. Virtual Earth™ mapping service is a trademark of Microsoft Corporation.

The names of other companies and products herein are trademarks or registered trademarks of their respective owners.

The content of this guide is furnished for informational use only, is subject to change without notice, and should not be construed as a commitment by Overwatch Systems, Ltd. Overwatch Systems, Ltd. assumes no responsibility or liability for any errors or inaccuracies that may appear in this book. This is not a comprehensive guide to the LIDAR Analyst software. Graphics and other illustrations are for reference only.

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The software and associated documentation whose export, transfer, diversion, disclosure and further publication is restricted by the applicable export laws and regulations of the United States of America, including the Export Administration Act of 1979, as amended, and the Export Administration Regulations. Violations of these laws and regulations are subject to severe civil, criminal and administrative penalties.

LIDAR Analyst 5.1.x Tutorial| i

Contents

Introduction .......................................................................................................................... 1

LIDAR: A Brief Overview .................................................................................................... 2

LIDAR Data ................................................................................................................... 2 First and Last Return ..................................................................................................... 3 Point Clouds .................................................................................................................. 3

LIDAR Analyst Basics ........................................................................................................ 4

Installation and Activation ................................................................................................... 5

Prerequisites and Installation ............................................................................................. 6

LIDAR Analyst for ArcGIS Prerequisites ........................................................................ 6 Before Installing LIDAR Analyst..................................................................................... 6 Installing and Activating Overview ................................................................................. 7 Installing LIDAR Analyst ................................................................................................ 7 Activating the LIDAR Analyst Extension ........................................................................ 8 Displaying the LIDAR Analyst Toolbars ......................................................................... 9 Optional LIDAR Analyst 3D Viewer ............................................................................... 9

Getting Started ................................................................................................................... 11

LIDAR Analyst Tools and the ArcMap Interface ............................................................... 12

Table of Contents (ArcMap) ........................................................................................ 13 Working with Layers in the Table of Contents .............................................................. 14 LIDAR Analyst Toolbars .............................................................................................. 19 Customizing a Toolbar ................................................................................................ 20 Edit Mode in ArcMap ................................................................................................... 23

Beginning Lesson .............................................................................................................. 25

Beginner Lesson .............................................................................................................. 25

Basic Workflow ............................................................................................................ 26 Basic Setup and Preparation ....................................................................................... 26 Lesson 1: Basic LIDAR Extraction ............................................................................... 29

Advanced Lesson ............................................................................................................... 65

Advanced Lesson ............................................................................................................ 66

Lesson 2: Point Cloud Extraction ................................................................................. 67

LIDAR Analyst Tools ........................................................................................................ 137

LIDAR Analyst Toolbars ................................................................................................. 137

LIDAR Analyst Menus ............................................................................................... 139 LIDAR Analyst Toolbar .............................................................................................. 156 LIDAR Analyst Bare Earth Toolbar ............................................................................ 159 LIDAR Analyst Building Edit Toolbar ......................................................................... 160 Customizing a Toolbar .............................................................................................. 162

ii | Contents

Point Cloud/LAS File Information.................................................................................... 171

LAS File Information ...................................................................................................... 171

Reviewing LAS File Header and Statistics ................................................................. 171

Building Edit Tools ........................................................................................................... 179

Using Building Edit Tools ............................................................................................... 179

Setting Tool Parameters ................................................................................................ 180

Setting the Building Auto-Split Tool Parameters ............................................................. 181

Setting the Building Reshape and Reorient Tool Parameters ......................................... 181

Setting the Courtyard Cleanup Tool Parameters ............................................................ 182

Using the Building Auto-Split Tool .................................................................................. 183

Reference - Building Edit Tools ...................................................................................... 185

Building Tool Settings Dialog ..................................................................................... 185

Building Reshape Tools ................................................................................................... 191

Building Reshape Tool with the SHIFT Key ................................................................... 192

Trimming Polygon Features ...................................................................................... 192 Cutting Holes in Polygons ......................................................................................... 193 Cutting a Polygon into Multiple Polygons ................................................................... 193

Building Reshape Tool with the CTRL Key .................................................................... 194

Closing Holes in Polygons ......................................................................................... 194 Creating New Polygons ............................................................................................. 194

Building Reshape Tool with the ALT Key ....................................................................... 195

Splitting Polygon Features ......................................................................................... 195

Building Reshape Tool Alone ......................................................................................... 196

Extending Polygon Feature ....................................................................................... 196 Merging Polygon Feature .......................................................................................... 196

Building Auto-Split Tools ................................................................................................ 197

Splitting Buildings Using the Building Reshape Tool ...................................................... 197

Adding to/Merging Buildings Using the Building Reshape Tool ...................................... 199

Removing Area from Buildings Using the Building Reshape Tool .................................. 200

Closing Holes in a Building Using the Building Reshape Tool ........................................ 201

Creating a New Building Polygon Using the Building Reshape Tool .............................. 202

Removing Building Area Using the Courtyard Cleanup Tool .......................................... 203

Reorienting a Building Using the Building Reorient Tool ................................................ 204

Regrowing Buildings Using the Building Reorient Tool ................................................... 205

Index .................................................................................................................................. 207

LIDAR Analyst 5.1.x Tutorial | 1

Chapter 1

Introduction Overwatch’s LIDAR Analyst® allows you to quickly and easily extract features using a point cloud or first and last return LIDAR data. LIDAR Analyst is a 3D feature extraction solution for airborne LIDAR (Light Detection and Ranging) data, supporting defense, academia, environmental organizations, and almost every field in the GIS industry requiring high resolution terrain information.

Through the power of automation, the LIDAR Analyst software radically simplifies the process of extracting bare earth, buildings, and trees/forest features. LIDAR Analyst provides tools for Automated Feature Extraction (AFE), Digital Elevation Model (DEM) editing, modification of bare earth surfaces, hillshading and relief, squaring of building footprints, and data attribution for buildings, tree points, and forest polygons.

In This Chapter

LIDAR: A Brief Overview ............................................................... 2 LIDAR Analyst Basics ................................................................... 4

2 | Introduction

Chapter 1

LIDAR: A Brief Overview

LIDAR is an acronym for Light Detection And Ranging. This recent technology, which reveals variations in elevation, is used for determining the shape of the ground surface with the inclusion of natural and man-made features. LIDAR data is used to map topographic features as well as the height and density of raised objects, such as trees and buildings, on the surface of the earth.

Raw LIDAR data, also called a point cloud, is collected from aircraft by firing laser beams to the earth. LIDAR sensors transmit laser light pulses in visible and near infrared wave lengths to the earth’s surface.

Upon hitting solid objects, the beams are reflected back to the LIDAR sensor. Elevation data (object height) are calculated by measuring the time required for the signal to travel to the object surface and back to the sensor. With this information, the actual height of buildings and other raised objects or topographic features can be calculated. Laser pulses can have multiple reflections from a single beam, enabling detailed modeling of terrain surface. Part of a beam can hit a solid object and reflect back to the sensor while the rest of the beam continues toward the ground. This commonly occurs in forested or urban areas.

Multiple reflections can determine intermediate surfaces such as tree canopy, providing elevation data for objects other than ground. Ideally, the first return hits the top leaves of the canopy and the last return travels through a gap to hit the ground under the canopy. Multiple reflections create a better surface model, since they enable the collection of more ground points in forested or urban areas.

LIDAR Data

LIDAR point data is collected in a swath. Each laser return results in a data point with x, y, and z coordinates, where x is longitude, y is latitude, and z is elevation.

The reflective intensity, or strength of the reflected laser pulse, is commonly collected along with the other data. Good intensity data produces an image comparable to a black and white photograph. Intensity data can be used for visualization of your data and referencing features for extraction.

The two primary results derived from raw LIDAR data are the last-return data file and the accompanying first-return data file.


LIDAR: A Brief Overview

First and Last Return

Each light beam transmitted, from an aircraft, to the earth results in one or up to five reflections. A reflection or return is defined as the portion of a light beam that hits the surface of an object and travels back to the sensor. In areas containing surfaces smaller than the beam radius, multiple reflections can occur.

When the light beam (or laser) comes in contact with an object in such a way that the incident energy is only partially reflected back to the sensor, the remaining incident energy continues traveling downward until it comes into contact with another solid object. I any additional objects, in the continuing path of the beam, reflect sufficient laser energy back to the sensor, will be detected.

The first portion of the beam, that hits an object such as a branch or leafy area of a tree, is reflected back to the sensor is called the first return. First return data contains elevations from the first surfaces the laser comes in contact with. The portion of the beam that strikes a final object (such as the ground) and goes back to the sensor is referred to as the last return. Last return data contains elevations from the subsequent hits and the final incident energy strike.

Since the first return data contains the elevations of the tallest features in a dataset (the light beam hits the highest object first) and the last return has the strongest probability of hitting the actual ground surface, using first and last return data is useful for extracting building, tree, and bare-ground elevations. Returns between the first and last returns often strike intermediate objects, such as tree branches, and are useful for studying the canopy structure of forest.

Point Clouds

Raw LIDAR data derived from a pulse returns is a point cloud. The multiple reflections of the laser beam create a multi-return point cloud. At the very least, the point cloud contains elevation values for all returns, with each point defined by the associated x, y, and z coordinate values.

The density of the point cloud is usually specified by the manager for the LIDAR project. Depending upon the LIDAR acquisition sensor and the format and fields requested by the project manager, the point cloud can store additional data such as return information, intensity, time, and aircraft altitude.

Point cloud data is stored in many different formats, from ASCII (text, CSV, etc.) to binary (bin, LAS, proprietary formats). Increasingly, due to user demand, point clouds are being delivered as LAS (Log ASCII Standard) files, which are standardized, typically smaller, and can be used in multiple applications.

4 | Introduction

Chapter 1

LIDAR Analyst Basics

LIDAR Analyst imports and processes data returns in several formats.

Import LIDAR data returns in a variety of point-feature and grid-data formats, including LAS, ASCII, GeoTIF, and ArcGRID

Convert LIDAR data returns in text file format to the LAS file format

Process elevation data in LAS file format or DEM raster format

Process data in different horizontal and vertical map units

Output terrain and features, including bare earth (raster), buildings (vector), trees (vector), and forests (vector)

Classify LAS point clouds based on LIDAR Analyst extractions and user settings

In addition, LIDAR Analyst provides precise extraction algorithms for bare earth, buildings, and trees and forest features, enabling faster processing, allowing larger datasets, and improving accuracy. The interface includes parameter customization to refine the level of detail in extraction of terrain and culture features.

Visualize LIDAR data with a powerful 3D visualization application, and enhanced analysis tools

Import point clouds stored in a text file or shapefile

Crop LAS files

Edit DEMs by adding/removing points when generating bare earth, and defining regions to which you can apply various DEM modification processes

Extract multi-component/complex buildings and update z-values and attributes after editing with building reshape, building auto-split, and courtyard cleanup tools

Batch process LIDAR extraction models on your local system or in a CONDOR cluster


Chapter 2

Installation and Activation

In This Chapter

Prerequisites and Installation......................................................... 6

6 | Installation and Activation

Prerequisites and Installation


LIDAR Analyst for ArcGIS Prerequisites

LIDAR Analyst requires the following prerequisites:

Platform Program

ou must have the ArcGIS® program installed on the computer on which you are installing LIDAR Analyst. Feature Analyst and LIDAR Analyst support versions 9.3, 10.0, 10.1 and 10.2 of ArcGIS.

Administrative Permission

Confirm you have Administrative Privileges on the computer on which you will be installing LIDAR Analyst. If you do not have Administrative Privileges, contact your System Administrator to install the product for you or request that you have read/write permissions for the installation directory.

The default installation directory for 32-bit systems is: C:\Program

Files\Overwatch\Geospatial Modules.

The default installation directory for 64-bit systems is: C:\Program

Files(x86)\Overwatch\Geospatial Modules.

Uninstall Previous Version

If you have a 4.x or 5.0 version of LIDAR Analyst installed on your computer, you must uninstall it before installing the new version. Also, some computer configurations will not allow the installation of version 5.1.x if you have a 3.x version installed. If this is the case, uninstall the 3.x version.

Software Requirements

LIDAR Analyst 5.1.x for ArcGIS® requires Microsoft .NET Framework 2.0 in order to install successfully. Upon installation this requirement will be checked and you will be notified if .NET needs to be installed.

Before Installing LIDAR Analyst

Before installing LIDAR Analyst ensure the following steps are complete.

Install ArcMap.

Ensure your computer has the proper system requirements.



Installing and Activating Overview

The LIDAR Analyst installation, licensing, and activation process is easy.

You need to:

1. Ensure you have all the necessary prerequisites.

2. Install and activate LIDAR Analyst as an ArcGIS extension.

3. Submit a license request and install the license received by Overwatch. If you are running the tutorial, you do not need to complete this step.

4. Configure the LIDAR Analyst toolbar to display in ArcGIS. In some cases, you may need to display the LIDAR Analyst toolbar. See Displaying the LIDAR Analyst Toolbars (on page 9) for more information.

This guide covers standard licensing installation. For more information about installation and licensing options, refer to the LIDAR Analyst Install Guide.

Note: You DO NOT need a license to run the LIDAR Analyst Tutorial.

Installing LIDAR Analyst

This procedure covers basic installation. For more information, refer to the installation guide.

To install LIDAR Analyst:

1. Double-click on the LIDAR_Analyst_5_1_ArcGIS.exe to run the install application. The Overwatch LIDAR Analyst 5.1 for ArcGIS – InstallShield Wizard dialog displays. You are prompted to wait while the installer is extracting the installation files. Once extraction is completed you are allowed to continue to the next step in the installation wizard.

2. Click Next. The LIDAR Analyst for ArcGIS License Agreement dialog box displays. Read the Software License Agreement and if acceptable, select I Accept and choose Next.

3. Read the Software License Agreement and if acceptable, select I Accept and click Next. The Customer Information dialog displays.

4. Enter User Name and Organization.

5. Once you have entered your information click Next, The Destination Folder page displays. Use this dialog to specify a custom installation location.

6. Click Next. The Setup Type page displays.

7. Select Complete and click Next to install all components and proceed directly to the Ready to Install the Program page. Otherwise, select Custom and click Next to configure optional features in the Custom Setup page. The optional features to install are the 3D Viewer and Tutorial Files. Once configured features are selected click Next to proceed to the Ready to Install the Program page.

8. Click Install to begin the installation process. Click Back to go to any previous pages.

9. Click Finish on the InstallShield Wizard Completed page to exit out of the installer.


Chapter 2

Activating the LIDAR Analyst Extension

Once LIDAR Analyst is installed, you must activate it as an extension of ArcGIS before you can run the application. Activation enables you to access the LIDAR Analyst toolbars and functions within the ArcGIS workspace.

To activate LIDAR Analyst:

1. Open ArcMap. ArcMap displays.

2. From ArcMap, select Customize > Extensions. The ArcMap Extensions dialog opens, displaying a list of registered extensions available for your version of ArcGIS.

Figure 1: Extensions Dialog

3. Select LIDAR Analyst, and then click Close. LIDAR Analyst is activated. The toolbar displays in ArcMap. If you successfully activated LIDAR Analyst and you don't see the toolbar, follow steps for Displaying the LIDAR Analyst Toolbars (on page 9).



Displaying the LIDAR Analyst Toolbars

LIDAR Analyst has its own toolbars that are accessed directly from ArcMap. It includes the default LIDAR Analyst, the Building Edit, and the Bare Earth toolbars. If you just activated LIDAR Analyst you may need to configure ArcMap to display the toolbars.

The LIDAR Analyst toolbars, as with other ArcMap toolbars, can be shown, hidden, and moved as preferred.

To display the LIDAR Analyst toolbars:

1. If needed, start ArcMap.

2. Do either of the following:

Choose Customize > Toolbars > LIDAR Analyst Toolbar.

Right-click the toolbar area, and select Customize > LIDAR Analyst toolbar from the menu.

The LIDAR Analyst toolbar displays in ArcMap.

Don't see the LIDAR Analyst toolbar?

Once you install LIDAR Analyst, you may need to display the LIDAR Analyst toolbar. Additional Overwatch commands are also available that can be added to any toolbar. See Customizing the Toolbar (see "Adding Tools to a Toolbar" on page 20) for more information.

Optional LIDAR Analyst 3D Viewer

The LIDAR Analyst 3D Viewer feature allows you to view point clouds, bare earth and LIDAR Analyst based feature extractions.

Installing LIDAR Analyst 3D Viewer

LIDAR Analyst 3D Viewer is part of the default install configuration of LIDAR Analyst.

When installing LIDAR Analyst, either select the Complete installation or if selecting a Custom install make sure the 3D Viewer feature is configured to install. If this is done, the 3D Viewer is installed as a part of LIDAR Analyst.


Chapter 2

Opening the 3D Viewer

Once you have installed LIDAR Analyst 3D Viewer, you can open the application.

To open LIDAR Analyst 3D Viewer:

Select Windows Start > Programs > All Programs > Viewer 3D > Launch Viewer 3D. The 3D viewer launches.

You can also open directly from the LIDAR Analyst or LIDAR Analyst 3D toolbars.

Click the Open 3D View button on the LIDAR Analyst (on page 19) or LIDAR Analyst 3D toolbars. Launching the 3D Viewer from within ArcGIS allows you to sync views between the 3D Viewer and ArcGIS.


Chapter 3

Getting Started

In This Chapter

LIDAR Analyst Tools and the ArcMap Interface ........................... 12

12 | Getting Started

LIDAR Analyst Tools and the ArcMap Interface


Once you have installed, licensed*, and configured ArcMap to display the LIDAR toolbars, you can start working with the available tools. LIDAR Analyst includes three toolbars - LIDAR Analyst, LIDAR Analyst Building Edit, and LIDAR Analyst Bare Earth. Additional commands and options are also available and can be added to any toolbar

LIDAR Analyst toolbars (A) can be docked at the top of the ArcMap interface. Most tasks are initiated from these toolbars or by using the layer shortcut menus in the ArcMap table of contents (B).

*Tutorial users do not need a license.

Figure 2: LIDAR Analyst Tools and ArcMap Interface



Table of Contents (ArcMap)

The ArcMap table of contents includes data frames and layers. Each layer has a shortcut menu with available options. You can also configure layer options depending on the type. For example, you can change the symbol settings.

Tutorial Note: When you open the LIDAR Analyst Tutorial Project, all the lessons in the Project are loaded into the ArcMap table of contents. Each lesson is contained in a separate data frame. Each data frame lists all the layers in the lesson.

The follow diagram is an example of some of the layer options available.

Figure 3: Table of Contents

a) Data frame - A data frame must be activated in order to work in it. Only one data frame can be active at a time. The active data frame name appears in bold letters.

b) Layer - Right-clicking a layer displays shortcut menu of options.

c) Expand/Collapse Layer - Click the plus [+] to expand layer or the minus [-] to collapse layer.

d) Symbol - Double-clicking the symbol (green shown) opens the Symbols dialog.

e) Band Information - Click the band to display a menu of options.

f) Color Ramp - Click the color ramp to open the Color Ramp dialog.

g) Shortcut menus - Right-click a layer displays a context menu. Options vary depending on layer selected.


Chapter 3

Working with Layers in the Table of Contents

The ArcMap table of contents includes several options for adjusting layers and accessing functionality.

Activating a Data Frame

A data frame must be activated to work on it. Only one data frame can be active at a time.

1. Right-click on the data frame in the table of contents (on page 13). A menu displays.

2. Select Activate. The data frame text changes to bold indicating the data frame is active.

Figure 4: Active Data Frame in ArcMap

Expanding and Collapsing Layers

You expand the data frame to show more information and collapse as needed.

Click [+] to expand the layers.

Click [-] to collapse layers.

Showing and Hiding Layers

The check box next to each file in the table of contents (on page 13) indicates whether or not the image is currently displaying in the workspace. Select or clear the check box next to the layer.



Changing Layer Symbology

Layer symbols are easily customized from the table of contents.

To change layer symbology:

1. Click the color symbol to the left of the text in the table of contents. The ArcMap Symbol Selector dialog displays.

Figure 5: Symbol Selector Dialog

2. Do any of the following:

Select an existing symbol from the list.

Create your own using the fill, outline, and other options.

3. Click OK. The symbol is updated in the table of contents as specified.


Chapter 3

ArcMap Layer Properties Dialog - Symbology Tab

The Symbology tab of the Layer Properties dialog is where you specify layer symbology.

Access Location:

ArcMap

Table of Contents: Right-click a layer > Properties. Click the Symbology tab.

Table of Contents: Click the symbol in the table of contents.

Figure 6: Symbology Tab

Symbology Tab Options

Show

Allows you to choose the display method for the image.

Import

Launches the import dialog and allows you to choose an image to import.

Display Background Value (R, G, B)

When selected, displays the background value of the image.

as

Displays RGB values as specified.

Display NoData as

Default settings are used to represent data.



Stretch

Type

Allows you to choose the stretch type from a predefined list of options. For example, Custom, Standard Deviations, Histogram Equalize and Minimum- Maximum are available.

Histograms

Opens the Histogram for <layer> dialog for you to setting per band.

Invert

When selected, inverts the stretch applied to the image.

Apply Gamma Stretch

When selected, applies a gamma stretch to the image.

Statistics

Allows you to choose the location from which to draw statistics.



LIDAR Analyst Toolbars

Many of the features and functions of the LIDAR Analyst application can be accessed from the LIDAR Analyst toolbars. The standard (default) toolbar includes a drop-down menu, and opens with the most commonly used tools and shortcut tool buttons.

LIDAR Analyst includes the following toolbars:

LIDAR Analyst Toolbar

LIDAR Analyst Bare Earth Toolbar

LIDAR Analyst Building Edit Toolbar

In This Section

LIDAR Analyst Toolbar ................................................................ 19 LIDAR Analyst Bare Earth Toolbar .............................................. 19 LIDAR Analyst Building Edit Toolbar ........................................... 20


The standard LIDAR Analyst toolbars open, by default, with the most commonly used tools. You can add or remove tool buttons to suit your needs.

Figure 7: LIDAR Analyst Toolbar


The Barth Earth toolbar provides tools for adding data points, removing ground clutter such as trees and buildings, reassigning, raising or lowering DEM heights, as well as replacing a DEM region.

Figure 8: LIDAR Analyst Bare Earth Toolbar


Chapter 3


The Building Edit toolbar provides tools for building settings, reshaping, cleanup, reorienting, squaring up, eroding, aggregating, smoothing features, and creating points in a building layer.

Figure 9: Building Edit Toolbar

Customizing a Toolbar

You can customize the LIDAR Analyst toolbar with any or all of the LIDAR Analyst tools, including shortcut tool buttons associated with menu commands.

Note: All <product _name> functions can be added as a tool button to the toolbar.

Adding Tools to a Toolbar

For your convenience, you have the option of customizing the toolbar with specific tools/commands.

To add tools to a toolbar:

1. Right-click on the LIDAR Analyst (on page 19) toolbar or click the drop arrow, then choose Customize from the shortcut menu. The Customize dialog box opens.

Figure 10: Customize Dialog

2. Select the Commands tab. The Commands (on page 168) tab displays.



3. Select one of the following in the Commands list box:

LIDAR Analyst Commands

LIDAR Analyst Tools

Overwatch Commands

Overwatch Tools

4. Select the tool you want to add to the toolbar from the Commands list box.

5. Click and drag the tool to the LIDAR Analyst toolbar. Release the tool on the toolbar where you want it to appear. The tool appears on the toolbar in the location where you placed it.

6. Continue to drag and drop tools on the toolbar, as necessary.

7. To save your customized toolbar for use with the current project only, select the Options tab of the Customize dialog. The Options tab displays.

Figure 11: Options Tab

8. Select Save all customizations to the document. The Save in Document dialog displays.

9. Choose OK to save the customizations to the current document.

10. To save the change to the base (normal.mxt) template, uncheck the Save all customizations to the document check box. This displays your customized toolbar in every new project you open.

11. Click Close.


Chapter 3

Removing a Tool from a Toolbar

It is easy to remove any tool or command from a toolbar. The Customize dialog must be opened first before you can remove a tool.

To remove a tool from a toolbar:

1. Do either of the following to open the Customize dialog:

Right-click on the LIDAR Analyst toolbar and select Customize on the shortcut menu.

Click the drop-down arrow on the toolbar and select Customize on the shortcut menu.

The Customize (on page 166) dialog displays. All buttons on the toolbar activate.

2. Do one of the following:

Left-click the tool and select Delete from the shortcut menu.

Figure 12: Tool Shortcut Menu

Drag the tool off the toolbar and release the mouse.

Resetting a Toolbar

The toolbar settings can be reset to their default. You must open the Customize dialog to reset a toolbar.

To reset the LIDAR Analyst toolbar:




The Customize dialog displays.

2. Select the Toolbars tab. The Toolbar tab displays.

3. Select the appropriate toolbar in the Toolbars list, and click Reset. The toolbar resets to its default setting.



Edit Mode in ArcMap

When a new feature class is created, it is automatically placed in edit mode. However, if you want to return to that file later and make changes, you need to enable Edit mode in ArcMap.

Manually Starting Edit Mode

You can manually start the edit mode should you need to work with a feature class.

To manually start feature class editing:

1. Highlight the feature class or object you wish to edit in the ArcMap table of contents (on page 13).

From the ArcMap Editor (on page 24) toolbar, select Editor > Start Editing. The tools needed for a basic LIDAR Analyst workflow are enabled on the LIDAR Analyst Bare Earth toolbar. The ArcMap Editor tools are enabled.

2. Select the Target drop-down arrow on the ArcMap Editing (on page 24) toolbar to select the feature class. The LIDAR Analyst Bare Earth (on page 19) toolbar is now enabled.

LIDAR Analyst applies the data frame’s spatial referencing to the new shapefile.

3. Make applicable edits.

Saving Edits and Stopping the Editing Process

When you are done editing a feature class, you can save your edits and end the editing session.

To save edits and stop editing options:

1. From the ArcMap Editor (on page 24) toolbar, select Editor > Save Edits from the drop-down menu. The edits are saved.

2. To stop the editing process, select Editor > Stop Editing on the drop-down menu.


Chapter 3

ArcMap Editor Toolbar

The ArcMap Editing toolbar is frequently used to start and stop editing mode when working with features and graphics. Refer to the ArcMap documentation for information about these tools.

Access Location:

ArcMap 10 and 10.1

Toolbar: Editor

Figure 13: ArcMap Editor Toolbar


Chapter 4

Beginning Lesson

In This Chapter

Beginner Lesson ......................................................................... 25

Beginner Lesson

LIDAR Analyst radically simplifies the process of extracting 3D features (bare earth surfaces, buildings, and trees), while providing tools for DEM editing, hillshading and relief, building squaring, and data attribution for buildings, tree points, and forest polygons.

The LIDAR Analyst Tutorial introduces you to the basic concepts and features of the LIDAR Analyst software and is the first step in learning to use LIDAR Analyst to extract 3D features. You can jump right into 3D feature extraction by using the LIDAR Analyst Tutorial dataset and documentation to guide you through basic bare earth extraction, extracting buildings, forests, and trees, and classifying the point cloud data. Using the LIDAR Analyst Tutorial, you can review the provided extraction results, run the data using the Tutorial lessons, and then experiment with the software using the provided dataset.

Overwatch would like to thank the National Oceanic and Atmospheric Administration (NOAA) and GeoICT (Geospatial Information and Communication Technology Lab)/Optech Incorporated for their permission to use these images in the development of our LIDAR Analyst tutorial.

26 | Beginning Lesson

Chapter 4

Basic Workflow

An established workflow enables you to streamline the work and focus on results. The LIDAR Analyst project workflow is a specific sequence of process steps designed to produce good results and improve efficiency and productivity.

Figure 14: LIDAR Analyst Workflow

Basic Setup and Preparation

Before starting the first Tutorial lesson, it is important to set up a project results folder and save a working copy of the Tutorial project.


Beginner Lesson

Create a Project Results Folder

Before you begin running the LIDAR Analyst Tutorial, it is important to set up a tutorial results folder on your local (C:\) drive. The tutorial results folder will serve as the designated location to output results generated from the Tutorial lessons and data to keep results organized and separate from the original dataset.

Figure 15: Sample LIDAR Analyst Results Folder Setup

Naming Results

Although it is normally recommended that you use the automatic default naming convention assigned by LIDAR Analyst when saving files (a name based on the name of the image and the process and including incremental numbering to identify multiple versions), it is important to use a different file naming convention when saving the files generated in the LIDAR Analyst Tutorial. Since you will be generating a second set of result files for the Tutorial lessons, it is important to name your files in a way to keep them separate from the results provided.

The LIDAR Analyst Tutorial Project results are named as follows:

TO_Core_last_DEM_AR.tif

TO_Core_last_DEM_AR_bareEarth.tif

TO_Core_last_DEM_AR_bareEarth_hillShade.tif

TO_Core_last_DEM_AR_bareEarth_ground_mask_modlayer

TO_Core_last_DEM_AR_bareEarth1.tif

TO_Core_last_DEM_AR_bareEarth_hillShade1.tif

Name your Tutorial results to include part of the data name, the process, and incremental numbering as necessary. For example:

TO_Core_last_DEM_AR.tif (provided)

FR_bareEarth.tif

FR_bareEarth_hillShade.tif

FR_bareEarth_ground_mask_modlayer

FR_bareEarth1.tif

FR_bareEarth_hillShade1.tif


Chapter 4

Good file organization will enable you to easily distinguish between the provided results and the results you generate.

Opening the Tutorial Project

The LIDAR Analyst Tutorial includes two lessons. When you open the LIDAR Analyst Tutorial, all the data and results for Lesson 1 and Lesson 2 are loaded for you in the table of contents. You will begin the Tutorial by using the data provided. After you run each process, you can compare your results easily with the Tutorial results provided.

You can exit the Tutorial at any time and return later to complete it. Simply, save your changes before exiting the application. The beginning lesson of the LIDAR Analyst Tutorial provides the basic concepts and workflow, while the second lesson covers the more advanced features of the application.

To open the tutorial project:

1. If needed, open ArcMap.

2. From the LIDAR Analyst (on page 19) toolbar, choose LIDAR Analyst > Help > Tutorial > LA Tutorial Project. The LIDAR Analyst Tutorial Project opens in a second instance of ArcMap. The Tutorial image and final result layers display in the workspace.

Saving Your Tutorial Project

When working in the LIDAR Analyst Tutorial, you should save your work periodically.

To save the tutorial project:

1. Select File > Save As on the ArcMap menu bar. The Save As dialog displays.

2. Navigate to C:\My_LA_Tutorial_Results\Lesson 1, enter a new name for your tutorial

project file.

3. Click Save. The project is saved.

Opening Your Saved Tutorial Project

You can open a previously saved tutorial project.

To open your saved project:

1. Select File > Open on the ArcMap menu bar. The Open dialog displays.

2. Navigate to C:\My_LA_Tutorial_Results\Lesson 1, select your tutorial .mxd file.

3. Click Open. Your saved tutorial project opens.


Beginner Lesson

Lesson 1: Basic LIDAR Extraction

In this first lesson, you will use the LIDAR Analyst default settings to familiarize yourself with LIDAR Analyst and quickly run through a basic extraction workflow. The basic workflow includes extracting bare earth, extracting buildings, and then extracting trees.

To begin, you will create a hillshaded DEM to improve visualization of your images. Next, you will extract bare earth from your pre-loaded first and last return DEMs. A bare earth layer essentially represents the ground surface as it would appear without high vegetation or man-made objects. Bare earth is like a DEM minus buildings, trees, and other large features.

The bare earth DEM is created by identifying ground regions, extracting points from these regions, and then interpolating a ground surface from these points. Ground regions are identified using slope, aspect, and other parameters.

With a good bare earth layer, you can then extract buildings. Buildings are one of the most important geospatial features for spatial analysis and mapping. Buildings are represented as red-outlined polygons. The buildings layer is a polygon shapefile, not a raster image. After generating the building layer, you will extract trees and forested areas.

Figure 16: LIDAR Extraction


Chapter 4

Opening the Tutorial Project

The LIDAR Analyst Tutorial includes two lessons. When you open the LIDAR Analyst Tutorial, all the data and results for Lesson 1 and Lesson 2 are loaded for you in the table of contents. You will begin the Tutorial by using the data provided. After you run each process, you can compare your results easily with the Tutorial results provided.

You can exit the Tutorial at any time and return later to complete it. Simply, save your changes before exiting the application. The beginning lesson of the LIDAR Analyst Tutorial provides the basic concepts and workflow, while the second lesson covers the more advanced features of the application.

To open the tutorial project:

1. If needed, open ArcMap.

2. From the LIDAR Analyst (on page 19) toolbar, choose LIDAR Analyst > Help > Tutorial > LA Tutorial Project. The LIDAR Analyst Tutorial Project opens in a second instance of ArcMap. The Tutorial image and final result layers display in the workspace.


Beginner Lesson

Creating a Hillshaded DEM

Hillshading allows you to add three-band (RGB), color-shading effects (values from 0 to 255) to aid in visualizing the features in the bare earth layer. Relief adds shadows and texture to the output image. These effects create a pseudo-3D image, which gives you clues (such as shadow and variations in lighting) about the elevation of the terrain. Hillshading the first-return DEM assists in visualizing buildings and other features with elevation values.

To create a hillshaded DEM:

1. Select the firstreturn_1m_dem.tif layer for display. The first return DEM displays in the workspace.

Figure 17: First and Second Return

2. From the LIDAR Analyst (on page 19) toolbar, do either of the following:

Click the Create Hill-Shade Image button .

Select LIDAR Analyst > Analysis > Create Hill-Shaded Image.

The Hill-Shade and Relief (on page 60) dialog opens.

3. Under Shading Style, select Elevation #1.

4. Accept the default settings for the other options and click OK. The Save Raster Data dialog opens.


Chapter 4

By default, LIDAR Analyst names the image in the Name field using the name of the first return image and the process (in this case, hillShade).

Figure 18: Hill-Shade DEM


Beginner Lesson

Bare Earth Extraction

The first step in a basic LIDAR extraction is to generate the bare earth surface. The bare earth extraction removes ground clutter, such as trees, buildings, cars, and other above ground objects to delineate the digital elevation model (DEM) or bare earth (BE) to best represent the topography.

You can complete bare earth extractions using either both first and last return data or a single return only. You can use either a raster image or an LAS file as the input. In this lesson, you will extract bare earth using first and last return DEMs. Using both first and last return LIDAR data usually enables the best bare earth results.

Prerequisites:

Ensure you have setup your project results folder and save a copy of the tutorial as described in Lesson 1.

To complete a bare earth extraction:

1. If necessary, right-click on the Exercise 1 data frame in the table of contents (on page 13) and select Activate. The data frame name, Exercise 1, displays in bold letters.

2. Select the firstreturn_1m_dem and the secondreturn_1m_dem layers for display. Deselect all other layers. The first and second return DEMs displays in the workspace.

Figure 19: First and Second Return


Click the Extract Bare Earth button .

Select LIDAR Analyst > Extraction > Extract Bare Earth.


Chapter 4

The Bare Earth Extraction (on page 48) dialog displays.

Figure 20: Bare Earth Extraction

4. Under Bare Earth Extraction Methods group box, select Method 1: Raster or Point Clouds.

5. Select the secondreturn_1m_dem.tif from the Single/Last Return drop-down menu.

6. Select the firstreturn_1m_dem.tif from the First Return drop-down menu. You may need to expand the dialog to see these options.

7. Under Map Units group box, select Horizontal units and Vertical units.

8. Accept the settings under Pre-process and Post-process. For detailed information about these options, see Bare Earth Extraction (on page 48) reference topic.

Note: A pre-process option runs on the input DEMs, while a post-process option refers to the

processing of the bare earth.


Beginner Lesson

9. Click the More button on the Bare Earth Extraction dialog. The dialog expands (on page 51) to show more options.

Figure 21: Bare Earth Expanded

10. Under Tree and Forest Parameters, deselect the Use average slope for tree mask check box.

11. Accept the remaining settings. The default extraction settings work for the majority of LIDAR extractions.

12. Click the Bare earth output [...] button ((bottom left-side) on the Bare Earth Extraction (on page 48) dialog. The Save Raster Data dialog displays. By default, LIDAR Analyst names the image in the Name field using the name of the last

13. Navigate to C:\My_LA_Tutorial_Results\Lesson 1 and name the file, bareEarth.tif.

Note: To complete this step, you need to complete the first tutorial on setting up project results

folder and save a working copy of the tutorial.

14. Click the Save button on the Save Raster Data dialog to save the file. The bare earth output displays in the Bare Earth Output field on the Bare Earth Extraction dialog.

15. Click OK on the Bare Earth Extraction dialog. The dialog closes.


Chapter 4

The LIDAR Analyst extraction progress window display showing the extraction progress. When the bare earth extraction is complete, the bare earth result file appears in the table of contents and displays in the workspace.

Figure 22: Bare Earth

LIDAR Analyst displays a message box asking if you want to generate a hillshade image for 'bareEarth.tif'.

16. Click Yes to create a hillshade. The Hill-Shade and Relief (on page 60) dialog displays. You are now ready to continue to the next topic - Generating a Hillshade Layer (on page 37).


Beginner Lesson

Generating a Hillshade Layer

Hillshading allows you to add three-band (RGB), color-shading effects (values from 0 to 255) to aid in visualizing the features in the bare earth layer. Relief adds shadows and texture to the output image. These effects create a pseudo-3D image, which gives you clues (such as shadow and variations in lighting) about the elevation of the terrain.

To generate a Hillshade layer:

1. If needed, complete the previous Bare Earth Extraction tutorial topic and ensure the Hillshade and Relief (on page 60) is displayed.

Figure 23: Hill-Shade and Relief

2. Set the following in the Hillshade and Relief dialog:

Accept the default settings for Lighting Altitude (45) and Lighting Azimuth (315). See Hillshade and Relief (on page 60) reference topic for other input options.

Deselect the Compute Shadow option.

Select Bare earth in the Shade Style group box.

Click OK.

The Save Raster Data dialog displays.

LIDAR Analyst names the image in the Name field using the name of the bareEarth image and the process (in this case, hillShade).

3. Review the default file name (bareEarth_hillShade.tif) and location

(C:\My_LA_Tutorial_Results\Lesson 1) for the bare earth, hillshade layer.

4. Click the Save button. The LIDAR Analyst progress window opens, displaying the progress of the hillshade layer.


Chapter 4

The bare earth, hillshade layer displays in the table of contents and in the workspace.

Figure 24: Bare Earth Hillshade Layer

Examining Bare Earth Results

The bare earth extraction process strips the image to the earth terrain. The shading shows the elevation changes within the image area.

Examine the bare earth layer. It should appear relatively smooth and topographically uniform with no raised features or distortion clearly visible.

The next step in most LIDAR extractions is to clean up any anomalies or false positives in the bare earth layer.

Note: Hillshaded DEMs are useful for reviewing building result accuracy.

LIDAR Analyst provides a series of tools designed to quickly clean up your bare earth results. In Lesson 2, you will find more information on the Bare Earth Modification tools and how to use them to get the best results from your bare earth layers.


Beginner Lesson

Building Extraction

Once you have created a good bare earth layer, you can use LIDAR Analyst to extract buildings. To extract buildings, LIDAR Analyst detects and isolates points in specific areas of an image that are within the set building parameters. The resulting buildings layer is a 3D shapefile (not a raster image) from which a 3-D building model can be displayed.

To extract buildings:


Click the Extract Buildings button .

Select LIDAR Analyst > Extraction > Extract Buildings.

The Building Extraction (on page 57) dialog displays.

When applicable, LIDAR Analyst detects and enters your bare earth layer in the bare earth field.

2. Verify that your bare Earth layer displays in the Bare earth field. If necessary, select the correct bare earth layer.

The last return LIDAR image and first return LIDAR image appear in their respective fields.

The Horizontal and Vertical Units selected for the bare earth extraction display under Map Units.

3. Click the Reset to Defaults. All settings reset to the default values.

Note: Since the system retains the settings from the last extraction. Resetting the defaults

each time you run an extraction ensures control over all the current settings.

4. Enter the following custom parameters in the center of the Building Extraction dialog. You may need to expand the dialog to show options.

Remove Buildings with area less than field: 5 square meters.

Remove Buildings with height less than field: 3 meters.

Texture variance for trees field: 50 percent.

Min difference between returns for trees: 0.1 meters.

Accept the default settings for the remaining options.

For additional input options, see the Building Extraction (on page 57) reference topic.

5. Click the Square-up options button or click the Square Up tab. The Building Square-Up Settings (on page 59) dialog/options displays.

6. Accept the other default settings under Building Square-Up Settings. For additional parameters, see the Building Square-Up reference topic.

7. Click OK.

8. Accept the default parameters under Extract tall buildings. For additional parameters, see the Building Square-Up Settings (on page 59) reference topic.

9. Click the Ellipsis [...] button next to the Building output field. The Save Feature Data dialog displays. LIDAR Analyst suggests a name based on the name of the last return and the process (in this case, buildings).

10. Navigate to C:\My_LA_Tutorial_Results\Lesson 1 and name the file buildings.shp.

11. Click Save. The Buildings layer filename appears in the Building output field.


Chapter 4

12. Click OK on the Building Extraction (on page 57) dialog. The progress window opens,

displaying the progress of the building extraction. When the building extraction is complete, the buildings extraction layer appears in the table of contents and in the active workspace.

Figure 25: Building Extraction


Beginner Lesson

Viewing the Attribute Table

Without having ArcScene, ArcGlobe or Overwatch's new 3D viewer, you can view the 3D attributes for your building polygons by opening the Attribute Table from the ArcMap table of contents.

To view the attribute table from ArcMap:

1. Right-click any building layer in the table of contents (on page 13).

2. Select Open Attribute Table. The Attribute Table displays. Notice the Height columns. These show the Z-values for each polygon.

Figure 26: Attribute Table

3. When you are done viewing the table, click the Close [X] button.


Chapter 4

Tree Extraction

After generating a satisfactory building layer, the next step is to extract the trees and/or forested areas. Extracting the vegetation in your dataset completes the LIDAR Analyst extraction process. To extract vegetation, LIDAR Analyst detects and isolates points in specific areas of an image. The resulting trees layer is a 3D shapefile (not a raster image).

To extract trees:

1. If needed, complete the Building Extractions.

From the LIDAR Analyst (on page 19) toolbar, do either of the following:

Click the Extract Trees button .

Select LIDAR Analyst > Extraction > Extract Trees.

The Tree Extraction (on page 62) dialog displays. When applicable, LIDAR Analyst enters the bare earth layer in the bare earth field.

Figure 27: Tree Extraction

2. In the Tree Extraction dialog do the following:

Verify that your bare earth layer displays in the bare earth field. If necessary, select the correct bare earth layer. The last return LIDAR image, and the first return LIDAR image if used, appear in the respective fields.

Verify that your buildings layer displays in the Buildings field. If necessary, select the correct buildings layer. The Horizontal and Vertical Units selected for the bare earth extraction display under Map units.

Click the Reset to Defaults button. All settings reset to default values.


Beginner Lesson

3. Under Extraction Method, select Method 2: Variable window search (better at getting accurate crown widths). For more information, see Tree Extraction (on page 62) reference topic.

4. Under Output Files, select the Tree Points option. The Save Feature Data dialog displays. LIDAR Analyst suggests a name based on the name of the last return and the process (in this case, trees).

5. Navigate to C:\My_LA_Tutorial_Results\Lesson 1 and name the file trees.shp.

6. Click Save. The Tree Extraction dialog is now active.

7. Ensure the following default settings are specified:

Predominant tree forest/forest type: Mixed

Minimum tree height: 3 meters

Maximum tree height: 40 meters

For additional options, see Tree Extraction (on page 62) reference topic.

8. Click OK. The LIDAR Analyst extraction process dialog displays showing the extraction process. When the extraction completes, LIDAR Analyst places the new layer in the active workspace. Each individual tree is represented by a yellow point.

Figure 28: Forest Extraction


Chapter 4

Forest Extraction

Using the same image, you can extract stands of trees or forests, rather than individual trees. Follow the instructions below to generate different tree extraction results.

Note: Although run separately here, you can run the tree and forest extractions at the same time and the extraction process will return two layers simultaneously.

To extract a forest:


Click the Extract Trees button .

Select LIDAR Analyst > Extraction > Extract Trees.

The Tree Extraction (on page 62) dialog displays. When applicable, LIDAR Analyst enters the bare earth layer in the bare earth field.

2. Verify that your bare Earth layer displays in the bare earth field. If necessary, select the correct bare earth layer.

The last return LIDAR image and the first return LIDAR image appear in the respective fields.

When applicable, LIDAR Analyst automatically enters the building layer in the Buildings field.

3. Verify that your buildings layer displays in the Buildings field. If necessary, select the correct buildings layer.

The Horizontal and Vertical Units selected for the bare earth extraction display under Map units.

4. Click the Reset to Defaults button on the Tree Extraction (on page 62) dialog.

5. Under Extraction Method, select Method 2: Variable window search (better at getting accurate crown widths).

6. Under Output Files at the bottom of the dialog box, deselect Tree Points and select Forest Areas. The forest parameters in the center of the dialog box become available.

The Save Feature dialog displays.

7. Type a name and click Save. The file name appears in the Forest Areas field under Output Files.

8. Ensure the following default settings are specified:

Predominant tree forest/forest type: Mixed

Minimum tree height field: 3 meters

Minimum size of a forest field: 600 meters

See the Tree Extraction (on page 62) reference topic for more information about forest parameters.

9. Click OK. The LIDAR Analyst progress window opens, displaying the progress of the forests extraction.

When the forest extraction is complete, the forests extraction layer appears in the table of contents and in the active workspace.


Beginner Lesson

Figure 29: Forest Extraction

Each forest area is represented by a polygon.

Notice that the forest areas do not include all stands of trees.

Trees not included in forest results did not meet the set criteria for stands greater than 600 meters.

Note: To get a better view of the forest layer, turn off the trees layer.

10. Save tutorial project.

You are now ready to continue on to the Advanced Lesson 2.


Beginner Lesson

Reference: Lesson 1

In This Section

Bare Earth Extraction Dialog ....................................................... 48 Bare Earth Modification Settings Dialog ...................................... 55 Building Extraction Dialog ............................................................ 57 Square-Up Tab (Formerly) Dialog - Building Extraction Dialog .... 59 Hill-Shade and Relief Dialog ........................................................ 60 Overwatch Progress Window ...................................................... 61 Tree Extraction Dialog ................................................................. 62


Chapter 4

Bare Earth Extraction Dialog

The Bare Earth Extraction dialog is used to create and configure bare earth settings. You can specify returns, map units, extraction, as well as pre and post processing options.

Access Location:

LIDAR Analyst

Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Extraction

Toolbar: LIDAR Analyst

Command: Extract Bare Earth

Doc Id: 9806



Single/last return

Select a single/last return file from the drop-down menu or launch the LAS File Selector dialog.

First return

Select a first return file from the drop-down menu or launch the LAS File Selector dialog.


Beginner Lesson

Map Units

Horizontal units

Allows you to choose the horizontal units for the bare earth extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Allows you to choose the vertical units for the bare earth extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Output Resolution (Point clouds only)

Manually specify cell size

If extracting bare earth from LIDAR point clouds, choose this option to manually specify the cell size of the output bare earth in map units. You should select this option if you already know the native point spacing of the input point clouds or if you want to output a bare earth at a different resolution than the point spacing of your input point clouds.

Estimate Cell Size

If extracting bare earth from LIDAR point clouds, choose this option to allow LIDAR Analyst to automatically detect the point spacing of the LIDAR point clouds. This information is used by LIDAR Analyst to set the cell size of the output bare earth raster.

Bare Earth Extraction Method

Method 1: Rasters or Point Clouds

Select this option to find ground points that are not close to non-ground objects, such as buildings and trees.

Method 2: Point Clouds

Select this option for extracting bare earth from LAS point clouds. This option works well on just about any LAS point cloud but especially well on dense forests. Selected by default.

Use existing ground points are used if this option is checked.

Pre-process

Auto-detect no-data regions

Large, flat areas of 100 square meters or more that are filled with a single value or no value are considered "no-data" regions. Bodies of water, which produce inaccurate LIDAR values, are typical of such resulting features. Selecting this option enables a search for no-data regions in the DEMs and removes such regions from the list of regions that will be processed for bare earth. Since large, perfectly flat regions do not occur naturally, selecting this option will produce better results. The option is selected by default.

Remove spikes and pits before processing

Selecting this option enables the search and removal of spikes and pits caused by anomalies in the input DEMs. Use this option only if the LIDAR data was not cleaned by the vendor. It is better to run this process as a separate, post-processing option, where you have more control over the removal parameters. By default, this option is not selected.

Note: If you know that your data does not have any large flat regions, clear this option to speed up processing time.


Chapter 4

Post-process

Remove negative nDSM regions

Since the extracted bare earth layer is an estimate of the bare-ground with features removed, it can lead to a normalized Digital Surface Model (nDSM) with negative values. The negative nDSM value corresponds to an area where the extractor estimated the bare earth surface to be higher than the actual surface height. These regions can therefore be safely set to the actual DEM height. A flattened DEM model is obtained using the formula: nDSM = DEM – bare earth.

Selecting this option results in all nDSM regions being replaced with last-return DEM values, thus setting those regions to an nDSM value of zero. If, after running a preliminary bare earth extraction, you find large height variations in your bare earth, you can try selecting this option and running your bare earth extraction again. By default, this option is not selected.

Smooth bare earth using low-pass filter; removes cars, shrubs, and low height objects

Selecting this option runs a Low-Pass Filter (LPF) on the extracted bare earth. Through a smoothing effect, the LPF removes the appearance of cars, shrubs, and low objects from the bare earth. By default, this option is not selected.

Bare earth output

Displays the output location for the bare earth extraction.

Reset to defaults

Resets all bare earth extractions to the default settings.

More

Expands the dialog to include more advanced bare earth extraction options.

Run Visible Extent

Runs as specified.

Preview

Allows you to preview the bare earth extraction with the chosen settings.


Beginner Lesson

Bare Earth Extraction (Expanded Method 1) Dialog

The Bare Earth Extraction dialog expands to show additional options.

Figure 31: Bare Earth Extraction Expanded

Bare Earth Extraction (Expanded) Options

Tree and Forest Parameters (Method 1)

Minimum slope for tree regions

Regions of the DEM with a slope greater than this value will be considered tree regions. The default is 10 degrees.

Minimum texture for tree regions

Regions of the DEM with a texture greater than this value will be considered tree regions. Texture values are derived from the aspect of the last-return DEM. The default is 80 percent.

Minimum difference between returns for tree regions

Any pixel where the elevation difference between first and last returns is greater than this value will be considered a tree region. Note: Use only when you are processing both first-and last-return data. The default is 0.3 meters.

Minimum forest size

Tree regions with an area greater than this value will be considered forest. The default is 10,000 square meters.

Sample 1 point in forest regions for every <value>

In forested areas, a ground point (an interpolation point) will be sampled from the lowest elevation value that occurs in a square of the defined area.


Chapter 4

Use average slope for tree mask

Check this option with bare earth extraction method 1 selected to perform LIDAR Analyst’s 4.2 method 1 extraction. Uncheck this option with bare earth extraction method 1 selected to perform LIDAR Analyst’s 4.2 method 2 extraction.

Ground Parameters (Method 1)

Slope threshold for flat ground (maximum slope in flat/steep ground)

Regions with a rate of change in slope lower than the slope threshold for flat ground will be considered flat ground, as opposed to steep ground. Thresholds are used to classify the maximum slope in flat ground and the maximum slope in steep ground as ground. The default slope threshold is 78 degrees. The default maximum slope in flat ground is 55 degrees and the default maximum slope in steep ground is 10 degrees.

Maximum slope in flat ground


Maximum slope in steep ground

Regions with a rate of change in slope greater than the slope threshold for flat ground will be considered steep ground, as opposed to flat ground. Thresholds are used to classify the maximum slope in flat ground and the maximum slope in steep ground as ground. The default slope threshold is 78 degrees. The default maximum slope in flat ground is 55 degrees and the default maximum slope in steep ground is 10 degrees.

Minimum area for ground regions

Defines the minimum area of a ground region. Does not determine the minimum polygon size in the final ground mask. The default is 35,000 square meters.

Sample 1 point in ground regions for every <value> (Method 1 and Method 2)

Defines the sampling rate of ground points. At least one ground point will be extracted for each window of this size within the ground regions. The default is 9 square meters.

Output last return if elevation difference between last return and ground surface estimate is (Method 1 and Method 2)

If the distance between the last-return (or single return) DEM and the extracted bare earth is lower than this threshold, then that region will be replaced with values from the last-return DEM. This step adds fidelity to the extracted bare earth. If this value is set to 0, then the output bare earth will be the original interpolated bare earth with post-processing clean-up applied. The default is 0.5 meters.

Return Parameters (Method 1)

Threshold difference between last return and ground surface estimate to ground mask

Defines the distance between the bare earth and the last-return (or single return) DEM. Regions with a distance lower than this threshold will be considered ground regions. The default is 0.1 meters.


Beginner Lesson

Cleanup bare-earth (post-process)

Selecting this option applies a "noise" filter to the bare earth. The noise filter removes small imperfections, resulting in a smoother looking bare earth. Use the slider bar to set smoothness parameters. The further to the right (Less smooth) the slider is moved, the lower the effect of the filter, the fewer regions to which the filter is applied, and the fewer imperfections that will be removed.

Setup Interpolator

Allows you to choose either Hierarchical Spline Interpolator of ArcGIS Spline Interpolator as the interpolation method.

Extraction Parameters (Method 2)

Max. building size (length)

The length of the largest building in the image. The default is 100 meters.

Max. height to jump for region growing

The maximum distance to jump in the Z direction for the region growing process. The region growing process extracts more ground points from the initial seed ground points. The higher the jump distance the more the number of points that are higher in elevation will be collected. The default is 0.35 meters.

Max. slope of ground regions

The maximum slope within the regions that were extracted as ground. Any regions with slope greater than the maximum slope will be filtered out. The default is 45 degrees.

Number of iterations for bare earth extractions

The number of iterations for the bare earth extraction to extract probable ground points. The default is 2.

Minimum area of extracted ground regions

The minimum area of extracted ground regions. Any regions smaller than this will be filtered out. The default is 30 square meters.

Interpolation

Hierarchical Spline Interpolator

The native interpolator in LIDAR Analyst is the Hierarchical Spline Interpolator.

ArcGIS Spline Interpolator

If you have ArcGIS Spatial Analyst installed and activated on your workstation, the additional interpolator, ArcGIS Spline Interpolator, appears in the list. The Hierarchical Spline Interpolator often works better on large datasets. However, you may need to experiment to see which option works better with your data.


Chapter 4

Masking Tab - Bare Earth Extraction Dialog

The Masking tab located in the Bare Earth Extraction dialog (expanded view) is used to select layers to mask.

Figure 32: Masking Tab


Beginner Lesson

Bare Earth Modification Settings Dialog

The Bare Earth Modification Settings dialog can be used to verify layer you wish to edit. If needed, you can change the layers.

Access Location:

LIDAR Analyst

Toolbar: LIDAR Analyst Bare Earth

Command: Delete Points from Bare Earth

Doc Id: 9994

Figure 33: Bare Earth Modification Settings

Figure 34: Process Bare Earth Modifications Dialog


Chapter 4

Bare Earth Modification Settings Options

Ground Points Layer

Allows you to choose the ground points layer.

Ground Mask Layer

Allows you to choose the ground mask layer.

Ground Mask Edits

Allows you to choose the ground mask edits layer.

Refresh Layer Lists

Refreshes the layer lists is outside lists were added to the drop-down menus.


Beginner Lesson

Building Extraction Dialog The Building Extraction dialog is used to se building removal parameters when running an extraction. For example, you can specify that any buildings with an area more than 30 square meters be removed. In addition, you can remove buildings by minimum and maximum height, as well minimum and maximum roof slope. From this dialog, you can launch the Square-Up dialog.

Access Location:

LIDAR Analyst



Command: Extract Buildings

Doc Id: 10107

Figure 35: Building Extraction Dialog

There are two building extractions dialogs with the similar options.

Figure 36: Building Extraction- Expanded View


Chapter 4

Buildings Extraction Options

Bare earth

Displays the bare earth file for the building extraction.

Single/last return

Displays the single/last return field.

First return

Displays the First Return field.

Horizontal units

Displays the horizontal units for the buildings extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Displays the vertical units for the buildings extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Extraction Method

Method 1 – Use this raster-based option to extract buildings from the bare earth raster. This is the original building extraction algorithm.

Method 2 – If the bare earth was generated from a point cloud, use this option to extract buildings directly from that point cloud. This approach works especially well with small building footprints.

Building output

Displays the name for the building output for the building extraction.

Reset to defaults

Resets all building extraction settings to the default settings.

<< Less button

Hides the Method 1, Method 2, Post-Process, and Square-Up tabs.

>> More button

Shows the Method 1, Method 2, Post-Process, and Square-Up tab


Beginner Lesson

Square-Up Tab (Formerly) Dialog - Building Extraction Dialog

This tab is accessible from the Buildings Extraction dialog.

Access Location:

Dialog: Building Extraction

Command: Square-up options

Figure 37: Square Up Options

Building Square-Up Options

Smoothing tolerance

Enter the number of meters a building vertex is allowed to move to smooth the building edges. Tolerance defines the maximum distance a point can move in relation to its neighboring vertices. Smoothing is accomplished with the Bezier Smoothing algorithm. The default is 1 meter.

Squaring Tolerance

Enter the number of meters that the vertices of an edge can move when snapping the edge vertical or horizontal. The default is 6 meters.

Consider all likely feature orientations when squaring up

Attempts many likely orientations and squares up features using the orientation that provides the best results. Selected by default.

Fine Tune Rotation

Fine-tunes the orientation angle of the polygon by the specified number of degrees. The default value is 0 degrees.

Consider adjoining features when computing orientation

Takes into account the orientation of adjoining features when squaring each feature. Not selected by default.


Chapter 4

Z-enable buildings using

Determines the z-values that are applied to the vertices of each building (including No z-values, Actual z-values, Min z-value, Max z-value, and Mean z-value).

Hill-Shade and Relief Dialog

The Hill-Shade and Relief dialog is where you configure lighting, shadow and map units.

Access Location:

LIDAR Analyst

Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Analysis


Command: Create Hill-Shaded Image

Doc Id: 9918


Hill-Shade and Relief Options

Lighting altitude

Allows you to set the lighting altitude. Altitude is the slope or angle of the illumination source above the horizon. The units are in degrees, from 0 (on the horizon) to 90 degrees (overhead). The default is 45 degrees.

Lighting azimuth

Allows you to set the lighting azimuth. Azimuth is the angular direction of the sun, measured from north, in clockwise degrees from 0 to 360. An azimuth of 90 is east. The default is 315 degrees.

Compute shadow

When selected, provides additional visualization.

Shading Styles

Elevation #1

The default for interpolating to raster.


Beginner Lesson

Elevation #2

Use this option on the second file when you want to display both first and LAS (Point Cloud) returns and be able to distinguish between the two.

Note: Elevation #1 and Elevation #2 are best used to represent first and last return DEMs,

respectively.

Bare earth

Use this option for the extracted bare earth. Creates an RGB hill-shaded image with a specific color-map.

Full spectrum

Use this option for creating an RGB hill-shaded image with the full color map range.

Partial spectrum

Use this option for creating an RGB hill-shaded image with a partial color map range.

Relief only

Use this option for creating a shaded (relief) gray-scale image that has a 3D appearance.

Map Units

Horizontal units

Allows you to choose the units of measurement for the horizontal units.

Vertical units

Allows you to choose the units of measurement for the vertical units.

Overwatch Progress Window

The Overwatch Progress Windows shows the status after most operations. The information reported varies depending on the task initiated. The window looks similar to the following:

Figure 39: Overwatch Progress Window


Chapter 4

Tree Extraction Dialog

The Tree Extraction dialog is used to specify tree and forest extraction settings. You can optimize results for dense forests or more accurate crown widths.

Access Location:

LIDAR Analyst



Command: Extract Trees

Doc Id: 10130


Tree Extraction Options

Bare earth


Single/last return


First return

Displays in the First Return field.

Buildings

Sets the buildings file used in the tree extraction.


Beginner Lesson

Horizontal units

Sets the horizontal units for the tree extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Sets the vertical units for the tree extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Method 1: Fixed window search

Extraction method for the tree extraction process (better for dense forests).

Method 2: Variable window search

Extraction method for the tree extraction process (better at getting accurate crown widths).

Figure 41: Tree Extraction Process Diagram

Note: Forest parameters are not available unless you select the Forest option at the bottom of

the dialog and designate a file output

Predominant tree/forest type

Set the predominant tree/forest type to match the type of trees present in the data. If most of the trees are either deciduous or coniferous, then select the corresponding tree type option. Select ‘Mixed’ if the data contain a blend of deciduous and coniferous trees. Select ‘Deciduous’ or ‘Coniferous’ if the data is mostly one type of tree. Selecting the appropriate type increases the accuracy of the tree extraction and attribution. The default setting is "Mixed".

Minimum tree height

Enter the minimum tree height to extract. The minimum tree height determines the minimum height a potential tree point has to have in order to be classified as a tree. Set this value appropriately for the data being processed. The minimum tree height is measured from the highest point of the tree crown to the ground (the length between A and C in the above diagram). The default is 3 meters.


Chapter 4

Maximum tree height

Enter the maximum tree height to extract. The maximum tree height determines the maximum height a potential tree point has to have in order to be classified as a tree. Set this value appropriately for the data being processed. The maximum tree height is measured from the highest point of the tree crown to the ground.

Typical tree height

Enter the average height of the tree to extract that is representative of the height of the trees you want to extract. Height is measured at the highest point of the tree crown, from (A) to (C) in the diagram above. It should be noted that setting the value too high will decrease the number of tree points extracted. The default is 40 meters.

Minimum size of a forest

Enter the minimum forest size that LIDAR Analyst should extract in a forest extraction. Available only when the Output forest areas option is selected. Determines how large of an area an extracted forest has to cover in order to be kept in the final output. The default is 600 square meters.

Tree points

Select Tree Points to return a point vector file showing individual trees. The default is selected.

Forest areas

Select to return a polygon vector file showing trees grouped together in forests or stands. When selected the Minimum size of a forest, becomes available. The default is selected.

Reset to defaults

Resets all tree extraction settings to the default settings.


Chapter 5

Advanced Lesson

In This Chapter

Advanced Lesson ........................................................................ 66

66 | Advanced Lesson

Advanced Lesson

Advanced Lesson

In the Beginning Lesson of the Tutorial, you learned the basic features of LIDAR Analyst. These included a simple workflow comprising three extractions, bare earth, buildings, and trees and forest. You also learned how to improve visualization of your bare earth layer using hillshading.

The Advanced Lesson moves more quickly and assumes a simple working knowledge of the basic steps covered in the first extraction lesson. In Lesson 2, you will follow the basic workflow of a more advanced extraction problem, and learn some of the advanced features of LIDAR Analyst.

In Lesson 2, you will learn how to work with point cloud data (LAS files), from reviewing the associated file information to converting the LAS data to raster (DEMs) data prior to running the bare earth extraction.

Next, you will run a bare earth extraction using custom settings. The resulting bare earth layer should appear relatively smooth and topographically uniform with no raised features or distortion clearly visible. This lesson emphasizes the importance of creating a good bare earth layer, since you must have a clean bare earth surface in order to generate successful building and/or tree extractions.

LIDAR Analyst provides a series of tools designed to quickly clean up your bare earth results. You will also learn how to use the Bare Earth Modification tools to get the best results from your bare earth layers. Once you have a smooth bare earth layer, you will extract buildings and learn how to use the building edit tools. To complete the extraction process, you will extract vegetation using custom parameters.

Lastly, you will use LIDAR Analyst to classify the points in your LAS file into three categories: bare ground, buildings, and vegetation. Once classified, you can view a summary of the classification statistics for each classification type


Advanced Lesson

Lesson 2: Point Cloud Extraction

The LIDAR Analyst point cloud tools are designed to help you convert, interpret, view, and classify point cloud data. You can extract bare earth, buildings, and trees/forest directly from point cloud data, or you can convert the point cloud into raster format first and then extract features from the raster image(s). Converting the point cloud data to a DEM (raster) and then generating the hillshade layer provides a visual surface to lay the building results on to check for accuracy.

It is advantageous and often necessary to review the point cloud data header information in the LAS File Info window before converting the LAS file into raster format or running a bare earth extraction.

Figure 42: Point Cloud Extraction


Chapter 5

Activate Lesson 2

Exercise 2 data frame must be activated in the ArcMap table of contents to complete the lessons in this section.

To activate Exercise 2 data frame:

Right-click Exercise 2 data frame in the ArcMap table of contents (on page 13) and select Activate.The data frame name, Exercise 2, displays in bold letters.

Figure 43: Activate Lesson 2 in the Table of Contents

Selecting the LAS (Point Cloud) File

Before you start processing your LIDAR data, it is advantageous to convert your LAS data (point clouds) to DEMs (rasters). The resulting visual representation of your point cloud data will help you reference features prior to extraction, and especially during cleanup of your bare earth layer.

Note: It is important to review the LAS header information prior to converting the file.


Advanced Lesson

To select LAS (Point Cloud) file:


Click the Point Cloud to Raster with Filtering button .

Select LIDAR Analyst > Point Cloud Tools > Convert Point Cloud to Raster with Filtering.

The Point Cloud to Raster (on page 127) dialog displays.

Figure 44: Point Cloud to Raster

2. If a LAS file automatically displays in the Input File field, verify that is the TO_core_last.las file associated with the Tutorial data. If not, do the following:

a. Click the Input File Ellipsis button [...] to select a Point Cloud file. The LAS File Selector (on page 122) dialog displays.

b. Click the File Path Ellipsis [...] button. The Open LIDAR file dialog displays.

c. Navigate to the LIDAR Analyst Tutorial dataset c:\Overwatch Tutorials\GAS\ArcGIS\LA_ArcGIS\Exercise_2.

d. Select the TO_core_last.las file.

e. Click Open. The path displays in the File path field on the LAS File Selector dialog.

Figure 45: LAS File Selector

3. Click the More button. The LAS File Selector dialog box expands (on page 123) displaying additional file information, enabling you to review header information, which contains number of returns, approximate point spacing, and number of points by type, etc.

You are now ready to review the file. See Reviewing LAS File Information (on page 70).


Chapter 5

Reviewing LAS File Information

It is best to review the LAS information using the View LAS Header menu option prior to loading your data.

To review LAS file information:

1. If needed, complete steps for Selecting the LAS (Point Cloud) File. The LAS File Selector dialog is displayed with the path to file populated.

2. If the dialog is not expanded, click the More button. Review or verify the header information for the file in the LAS Header Information scroll list box in the LAS File Selector dialog (expanded view (on page 123)). The header information begins with LAS File Information and ends with vertical units.

Figure 46: LAS File Selector Dialog

3. Select All Returns from the Filter by drop-down list. The Return Filter matrix under Filter Properties reflects the selected option. See the LAS File Selector (on page 122) reference topic for more information about return options.


Advanced Lesson

4. Click OK. The LAS File Selector dialog closes and the Point Cloud to Raster (on page 127) dialog is now active.

The point spacing you enter is reflected in the X and Y Cell Size fields. Typically the point spacing is the same in the x and y direction or is assumed to be the point resolution.

The X and Y Cell Size fields and the corresponding Output raster properties fields on the Point Cloud to Raster dialog updates.

The number of columns and rows in the dataset display in the Output raster properties fields on the Point Cloud to Raster dialog.

5. Set the X and Y Cell Size to 0.6.

6. Make sure to check the Fill Holes in data option.

7. Accept the remaining default settings on the Point Cloud to Raster dialog.

You are now ready to run the file conversion.


Chapter 5

Example LAS File Information

The expanded LAS File Selector dialog displays the LAS file information. The first section, the LAS Header, is provided by the vendor.

Figure 47: LAS File Information Example

The second section, LAS File Statistics, is generated by LIDAR Analyst.


Advanced Lesson

Figure 48: LAS File Statistics

Running a File Conversion

Once you have selected the LAS file and reviewed the LAS file information, you can convert LAS/Point Cloud data to raster. It is important to review the LAS header information prior to converting the file.

To run a file conversion:

1. If needed, complete steps for Reviewing LAS File Information. The Point Cloud to Raster (on page 127) dialog is displayed.

2. Click OK. The Save Raster Data dialog displays. LIDAR Analyst names the image in the Name field using the name of the LAS file.

3. Navigate to C:\My_LA_Tutorial_Results\Lesson 2 and name the file DEM.tif.

4. Click the Save button. The Save as dialog closes and The LIDAR Analyst progress window opens, displaying the progress of the file conversion. When the file conversion is complete, the DEM raster file appears in the table of contents and displays in the workspace.


Chapter 5

Figure 49: File Conversion

LIDAR Analyst displays a message asking if you want to generate a hill-shade image for 'DEM.tif'.

5. Click Yes. The Hill-Shade and Relief (on page 60) dialog displays.


6. Do the following:

Verify the default settings for Lighting Altitude (45), Lighting Azimuth (315).

Select Compute Shadow.

Select Elevation #1 in the Shading Style group box.


Advanced Lesson

7. Click OK. The Save Raster Data dialog displays. LIDAR Analyst names the image in the Name field using the name of the raster image and the process (in this case, hillShade).

8. Navigate to C:\My_LA_Tutorial_Results\Lesson 2 and name the file

DEM_hillShade.tif.

9. Click Save. The LIDAR Analyst progress window opens, displaying the progress of the hillshade layer generation. The LIDAR Analyst progress window opens, displaying the progress of the hillshade layer generation.

The DEM raster hillshade layer displays in the table of contents and in the active workspace.

Figure 51: DEM Raster Hillshade Layer

Point Cloud Bare Earth Extraction

Using LIDAR Analyst, you can extract a bare earth surface from an LAS file, an interpolated first and last return DEM, or an all-returns DEM. A good bare earth model serves as a representation of a ground surface with all of the vegetation and man-made objects stripped away. The bare earth surface should have no raised features, distortion, or unusually smooth areas.


Chapter 5

To perform a point cloud bare earth extraction:


Click the Extract Bare Earth button .

Select LIDAR Analyst > Extraction > Extract Bare Earth.

The Bare Earth Extraction (on page 48) dialog displays.



a. In the Single/Last Return field, select To_core_last_DEM_AR.

b. In the First Return field, select None, since there isn't a first return. LIDAR Analyst attempts to detect the horizontal and vertical units associated with the image and if successful, will fill the fields under Map units with the values.

c. Review the values for Horizontal Units and Vertical Units under Map units.

d. Click the Reset to defaults button. All the settings reset to the default values.

e. Accept the settings under Pre-process and Post-process. For detailed information about these options, see Bare Earth Extraction (on page 48) reference topic.

f. Under bare earth Extraction methods, select Method 1: Raster or Point Clouds.

g. Click the More button on the Bare Earth Extraction dialog. The dialog expands (on page 51) to show extraction parameters.


Advanced Lesson

Figure 53: Bare Earth Extraction Dialog - Expanded (Method 1)


Accept the default settings.

Locate the untitled (Interpolator) field at the bottom of the dialog and select the Hierarchical Spline Interpolator from the drop-down list for generating the bare earth surface. The Hierarchical Spline Interpolator is the native interpolator in LIDAR Analyst. If you have ArcGIS spatial Analyst installed and activated on your system, the ArcGIS Spline Interpolator also displays in the list.

Click the Setup Interpolator button. The Hierarchical Interpolator (on page 120) dialog displays.


a. Accept the default settings or review other parameters in the Hierarchical Interpolator reference topic.

b. Click OK to close the dialog.

The Hierarchical Interpolator dialog closes and the Bare Earth Extraction dialog is now active.

5. Click the Ellipse [...] button on the bottom left of the dialog and to the right of the Bare Earth Output field. The Save Raster Data dialog opens. By default, LIDAR Analyst names the image in the Name field using the name of the DEM raster and the process (in this case, bareEarth).


DEM_bareEarth.tif.

7. Click Save. The Bare Earth Extraction dialog updates to show the output path to the file.


Chapter 5

8. Click OK on the Bare Earth Extraction dialog. The Overwatch extraction progress window

opens, displaying the progress of the bare earth extraction. LIDAR Analyst displays a message asking if you want to generate a hill-shade image for 'DEM_bareEarth.tif'.

Figure 54: Hillshade Image

9. Click Yes to create the hillshade layer. The Hill-Shade and Relief (on page 60) dialog displays.


Accept the default settings for Lighting Altitude (45) and Lighting Azimuth (315).

Select the Compute Shadow.

Select Bare earth under Shading style.

Click OK. The Hillshade and Relief dialog closes and the Save Raster Data dialog displays.


DEM_bareEarth_hillShade.tif.


Advanced Lesson

12. Click Save. The Overwatch extraction progress window opens. LIDAR Analyst generates the bare earth, hillshade layer and displays it in the table of contents and in the active workspace.

Figure 55: Final Hillshade Layer

13. Examine the hillshaded, bare earth layer. Look for distortion, raised or pitted features, or unusually smooth areas.


Chapter 5

Bare Earth Modification Layer

Using the Bare Earth Modification tools, you can correct areas of distortion, raised or pitted features, and unusually smooth areas before moving on to the building extraction. It is especially important to have a smooth or clean bare earth surface for successful building and tree extractions, since both processes rely on the bare earth to find and identify the building and tree points.

To modify the bare earth:

1. From the LIDAR Analyst (on page 19) toolbar, select LIDAR Analyst > Clean-up > Create Bare Earth Modification Layer. The Create Bare Earth Modification Layer (on page 118) dialog box opens, allowing you to create the modification layer. When applicable, LIDAR Analyst enters the bare earth layer in the bare earth field.

Figure 56: Create Bare Earth Modification Layer


a. Verify that your bare earth layer, DEM_bareEarth, displays in the bare earth field. If necessary, select the correct bare earth layer. The last return LIDAR image appears in the Single/Last Return field.

b. Verify that the Ground points layer, DEM_bareEarth_ground_pts.shp, displays in the Ground Points field. If necessary, click the ellipsis [...] button to the right of the field and select the correct ground-points layer. The ground-points layer contains the points that are automatically generated during the initial bare earth extraction process.

c. Verify that your Ground mask layer, DEM_bareEarth_ground_mask.shp, displays in the Ground Mask field. If necessary, click the ellipsis [...] button to the right of the field and enter the correct ground mask layer. The ground mask layer, which represents bare earth, was generated during the initial bare earth extraction process also.

d. Under Outputs, click the ellipsis [...] button to the right of the Ground Points save path field.


Advanced Lesson

The Save Feature Data dialog box opens. By default, LIDAR Analyst names the image in the Name field using the name of the bare earth layer and the process (in this case, ground_pts_modlayer).


DEM_bareEarth_ground_pts_modlayer.shp.

4. Click Save. The file displays in the Ground Points Save Path under Outputs on the Create bare earth Modification Layer dialog box.

5. Repeat the same steps to create an output file:

Click the Ground mask save path ellipsis [...] button and name it DEM_bareEarth_ground_mask_modlayer.shp.

Click the Ground mask save path ellipsis [...] button and name it DEM_bareEarth_ground_mask_edits_modlayer.shp. The files display in their respective fields under Outputs on the Create Bare Earth Modification Layer dialog box.

6. Click OK to start the Create Bare Earth Modification process. The Overwatch progress window opens, displaying the progress of the modification layer.

LIDAR Analyst copies the ground mask and ground points modification files created with your original bare earth layer, saves them to the name and file location entered under Outputs, and loads them in the table of contents and workspace.

LIDAR Analyst creates a new ground mask edit layer, saves it to the name and file location entered under Outputs, and loads it in the table of contents and the workspace.

Figure 57: Mask Layer in the Table of Contents

The ground mask edits layer is empty until you edit the ground points modification layer.

The ground points modification layer is automatically in edit mode and all the editing tools on the LIDAR Analyst Bare Earth (on page 19) toolbar are activate for use.

The ground points modification layer has three categories that appear in the table of contents: Ground points (the interpolated points generated by LIDAR Analyst automatically during the original bare earth extraction), Add points (points you will create with the Add Points tool), and Delete points (points you will eliminate with the Delete Points tool).


Chapter 5

7. Examine your ground-mask modification layer (DEM_bareEarth_ground_mask_modlayer)

Figure 58: Ground Mask Modification Layer

8. Examine your ground points modification layer (DEM_bareEarth_ground_pts_modlayer).

Figure 59: Ground Point Modification Layer


Advanced Lesson

Bare Earth Modification Manual Edits

With the modification layers created, you can use the various cleanup tools and begin editing the modification layer.

In this lesson, you will manually add and delete ground points using the add and delete points tools on the LIDAR Analyst modification toolbar to correct elevation anomalies and refine the bare earth Modification layer.

To modify bare earth layer manually:

1. In the ArcMap table of contents (on page 13), turn on your Bare Earth Hillshade layer by checking the box in the table of contents and turn off all other layers.

2. Zoom to the central part of the image where there is a large raised feature using the ArcMap Zoom (on page 101) tools on the ArcMap Tools (on page 100) toolbar.

Figure 60: Feature to Modify


Chapter 5

3. To delete points in area (A), display your Bare Earth Hillshade and Bare Earth Ground Points

layers only.

Figure 61: Delete Points in (A)

4. Ensure that you are in editor mode. If needed, select Editor > Start Editing on the ArcMap Editor (on page 24) toolbar.

5. Verify that your ground points modification layer is the active layer.

6. Click the Delete Points from Bare Earth button on the LIDAR Analyst Bare Earth (on page 19) toolbar. The Bare Earth Modification Settings (on page 55) dialog displays with the layers for editing highlighted.

7. Verify that the layers displaying in the Bare earth Modification Setting dialog are the ones you want to edit. If necessary, select the correct layer in each field.


Advanced Lesson

8. Zoom in on area (A), the large raised feature in the left center of the image.

Figure 62: Area to Select

9. Draw a polygon around the points that occur on the non-ground regions. The pointer changes to a crosshair when you move over the image in the workspace.

10. Double-click to close the polygon. The ground points within the area where you drew the polygon turn red, indicating they are selected for removal.

Figure 63: Red Indicates Points are Selected for Removal

11. When you complete the modifications, select Editor > Save Edits on the ArcMap Editor toolbar.

12. Select Editor > Stop Editing on the ArcMap Editor toolbar.

13. Zoom out to review the edits on the Ground Points Modification Layer. Points marked for deletion display in red.


Chapter 5

Processing Bare Earth Modifications

Once you have marked points for addition and deletion on the bare earth modification layer, you can process the changes and generate a new bare earth layer.

To process bare earth modifications:

1. From the LIDAR Analyst (on page 19) toolbar, select LIDAR Analyst > Clean-up > Process Bare Earth Modifications. The Process Bare Earth Modifications (on page 129) dialog displays. The Map units fields display the map units selected when you generated your original bare earth layer.

Figure 64: Process Bare Earth Modifications

When applicable, LIDAR Analyst enters your bare earth layer in the bare earth field.


a. Verify that your original bare earth layer (DEM_bareEarth.tif) displays in the bare earth field. If necessary, select the correct original bare earth layer. LIDAR Analyst displays the Single/Last Return file, and the First Return file if used, in the respective fields. When applicable, LIDAR Analyst enters the ground points modification layer in the Ground Points field.

b. Verify that the ground points modification layer (DEM_bareEarth_ground_pts_modlayer) created during the modification process displays in the Ground Points field. If necessary, select the correct ground points modification layer. When applicable, LIDAR Analyst enters the ground mask modification layer in the Ground Mask field.


Advanced Lesson

c. Verify that the ground mask modification layer (DEM_bareEarth_ground_mask_modlayer) created during the modification process displays in the Ground Mask field. If necessary, select the correct ground mask modification layer. When applicable, LIDAR Analyst enters the ground mask edits modification layer in the Ground Mask Edits field.

d. Verify that the ground mask edits modification layer (DEM_bareEarth_ground_mask_edits_modlayer) created during the modification process displays in the Ground Mask Edits field. If necessary, select the correct ground mask edits modification layer.

e. Click the Reset to defaults. All settings reset to the default values.

f. Choose the ellipsis [...] button to the right of the Bare Earth Output field.

The Save Raster Data dialog opens. By default, LIDAR Analyst names the image in the Name field using the name of the bare earth image and the process (in this case, the file is numbered 1 to follow the first bareEarth layer).


a. Navigate to C:\My_LA_Tutorial_Results\Lesson 2 and name the file

DEM_bareEarth1.img.

b. Click Save. The bare earth output displays in the Bare Earth Output field on the Process Bare Earth Modifications dialog.

4. Click OK. The Overwatch progress window opens, displaying the progress of the extraction. The modified bare earth result file appears in the table of contents and displays in the workspace.

LIDAR Analyst displays a message box asking if you want to generate a hillshade image.

5. Choose Yes to create the hillshade layer. The Hillshade and Relief (on page 60) dialog displays.

6. Accept the default settings and click OK. The Hillshade and Relief dialog closes and the Save Raster Data dialog displays.


DEM_bareEarth1_hillShade.img

8. Choose Save. The Overwatch progress window opens, displaying the progress of the hillshade. The generated hillshade image appears in the table of contents and in the workspace.

9. Examine your new bare earth layer.


Chapter 5

Point Cloud Building Extractions

As mentioned previously, it is critical to have a clean bare earth surface in order to get the best building and vegetation results possible. More important is the initial quality of the point cloud or raster data from which the bare earth is generated. Your building extraction can serve as an indication of the quality of the data and the effectiveness of your bare earth modifications. Once the bare earth is clean, you can begin the buildings and extraction.

To extract buildings:


Click the Extract Buildings button .

Select LIDAR Analyst > Extraction > Extract Buildings.

The Buildings Extraction (on page 57) dialog displays. When applicable, LIDAR Analyst detects and enters the bare earth layer in the bare earth field.

2. Verify that your DEM_bareEarth1.tif layer displays in the bare earth field. If necessary, select the correct bare earth layer. The last return LIDAR image appears in the Single/Last Return field. The Horizontal and Vertical Units selected for the bare earth extraction display under Map units.

3. Click the Reset to Defaults button. All settings reset to the default values.

4. Enter the following values:

Remove buildings with area more than: 65,000 square meters.

Remove buildings with height less than: 3 meters.

Minimum slope for building roofs: 15 degrees.

Maximum slope for building roofs: 40 degrees.

5. Click the Ellipse [...] button to the right of the Building Output field. The save Feature Data dialog displays.


DEM_buildings.shp.

7. Click Save. The Building filename appears in the Building Output field.

8. Click OK. The Overwatch progress window opens, displaying the progress of the building extraction. Your buildings extraction results layer appears in the table of contents and displays in the workspace.

9. Display only your building layer (DEM_buildings) and the TO_core_last_DEM_AR_hillShade layer.


Advanced Lesson

Edit Building

LIDAR Analyst provides a second toolbar with three building editing tools for cleaning up your building layers, and a tool for setting the options of the three editing tools. Your buildings layer must be in edit mode before you start.

To enable edit mode:

1. Select the building layer in the table of contents (on page 13).

2. From the ArcGIS Editor toolbar, select Editor > Start Editing. The LIDAR Analyst Building Edit toolbar displays.

Setting Tool Parameters for Courtyard Cleanup

Before you use the building edit tools, you must set the parameters for each tool function. The

parameters are set for the three tools using the Building Edit Tool Options tool. The Building Edit tools can only be used after a bare earth DEM is identified in the Building Tool Settings dialog box. In addition, the bare earth DEM, the building layer, and the Single/ Last Return must be loaded in the table of contents.

To set tool parameters for courtyard cleanup:

1. Click the Building Edit Tool button on the LIDAR Analyst Edit Building (on page 20) toolbar. The Building Tool Settings (on page 113) dialog displays. When applicable, LIDAR Analyst detects and enters the bare earth layer in the bare earth field.

2. Verify that your bare earth layer (DEM_bareEarth1.tif) displays in the bare earth field. If necessary, select the correct bare earth layer.

The building layer appears in the Building Layer field.

Verify that the correct building layer displays in the Building Layer field.

3. Click the Show Settings buttons. The dialog box expands to display the building tool options.The Single/Last Return field displays the last return image used to generate your bare earth and building layers.


Chapter 5

4. Select the Courtyard Cleanup Tool tab on the Building Tool Setting dialog. The Courtyard

Cleanup Tool tab displays.

Figure 65: Courtyard Cleanup Tool Tab

5. Click the Reset to defaults button. All settings on the Courtyard Cleanup Tool tab reset to the default values.

6. Enter the following custom settings for the Courtyard Cleanup tool:

Height Sensitivity field: 5.

Accept the default settings for the remaining options.

For additional information, refer to the Building Tool Setting reference topic.

7. Leave the Building Tool Settings dialog open on your desktop. Continue to the next procedural topic Using the Courtyard Cleanup.

Using Courtyard Cleanup

Once you have setup tool parameters you can perform the cleanup.

To use the Courtyard Cleanup tool:

1. Display only your building layer (TO_core_last_DEM_AR_buildings) and your hillshaded DEM (TO_core_last_DEM_AR_hillShade).

2. Using the ArcMap Zoom tools, zoom in on the building in the upper left corner of the image. Choose the Courtyard Cleanup tool on the toolbar. The pointer changes to a crosshair when you move over the image in the workspace.

3. Click in the building polygon. LIDAR Analyst automatically edits the courtyard areas in the selected polygon. The system identifies multiple courtyards in the building, based on the parameters entered in Building Tool Settings dialog box.

4. Zoom in on the building just below the center portion of the image. This time, with the Courtyard Cleanup tool still selected, draw a stretchy box over the building courtyard area.

5. LIDAR Analyst automatically edits the single courtyard area in the selected polygon.


Advanced Lesson

Using the Building Auto-Split Tool

The Building Auto-Split tool allows you to split building polygons.

1. Click the Building Auto-Split Tool (on page 114) tab on the Building Tool Setting dialog box.

2. Click the Reset to defaults. All settings on the Building Auto-Split Tool tab reset to the default values.

3. Accept the default settings for all options.

4. Using the ArcMap Zoom tools (on page 101), zoom in on the hook-shaped building in the middle of the image.

5. Click the Building Auto-Split button on the LIDAR Analyst Bare Earth (on page 19) toolbar. The pointer changes to a crosshair when you move over the image in the workspace.

6. Click in the building polygon. LIDAR Analyst automatically splits the building polygon into multiple components.

7. For extra practice, use the Courtyard Cleanup and the Building Auto-Split tools to edit the two buildings identified in the images below.


Chapter 5

Figure 66: Building Auto-Split

8. Click the Close button in the top right corner to close the Building Settings dialog when you are done making edits.

9. Select Editor > Save Edits on the ArcGIS Editing toolbar.

10. Select Editor > Stop Editing on the ArcGIS Editing toolbar.


Advanced Lesson

Squaring up Buildings

Once buildings have been extracted, they can be squared up.

To square up buildings:

1. Ensure the building layer secondreturn_1m_dem_buildings in the table of contents (on page 13) is highlighted.


From the LIDAR Analyst (on page 19) toolbar, select LIDAR Analyst > Enhancement > Square Up Buildings.

Click the Square Up Building button on the LIDAR Analyst Building Edit (on page 20) toolbar.

The Square Up Building (on page 132) dialog displays. When applicable, LIDAR Analyst detects and enters your bare earth layer in the bare earth field.

Figure 67: Square Up Buildings

3. Select applicable shape preview button from the Real-Time Preview group box.

4. Click OK. The Overwatch progress windows displays with showing squaring up status. When complete, the selected shapes display, in the Main Viewer, with the options you selected.


Chapter 5

Reviewing Building Modifications

The LIDAR Analyst Tutorial provides a buildings modification layer for your review.

To review building modifications:

1. Toggle between your DEM buildings results layer and the TO_core_last_DEM_AR_modified buildings layer to compare building edit results.

2. Compare your building edits with the Tutorial building edit results provided.

Viewing Building Attributes

To view building attributes:

1. Right-click on your buildings result layer and select Open Attribute Table on the shortcut menu. The Attribute table displays.

2. Click Close [X] when finished.

Point Cloud Tree Extraction

To extract trees:

1. From the LIDAR Analyst (on page 19) toolbar, select LIDAR Analyst > Extraction Extract Trees. The Tree Extraction (on page 62) dialog displays.

2. Verify that your modified bare earth layer (DEM_bareEarth1) displays in the bare earth field. The single/last return LIDAR image appears in the Single/Last Return field.


Advanced Lesson


3. Click Reset to Defaults buttons. All settings reset to the default values.

4. Under Extraction Method, select Method 2: Variable window search (better at getting accurate crown widths).

5. Under Output Files at the bottom of the dialog box, clear Forest Areas and select Tree Points.

6. If necessary, select the Ellipsis [...] button to the right of the Tree Points output field. The Save Feature Data dialog displays.

7. Navigate to C:\My_LA_Tutorial_Results\Lesson 2 and name the file DEM_trees.

8. Click Save. The trees filename appears in the Tree Points field under Output files

9. Accept the following default settings for the tree parameters in the center of the dialog:

Predominant tree/forest type: Mixed.

Minimum tree height field: 3 meters.

Maximum tree height: 40 meters.

10. Click OK. The LIDAR Analyst extraction process dialog box opens, displaying the progress of tree extraction.


Chapter 5

Point Cloud Classification

Once you have extracted your bare earth, buildings, and vegetation features, you can use LIDAR Analyst to classify the points in your LAS file. Raw LIDAR point cloud data in LAS file format can be classified into three categories: bare ground, buildings, and vegetation.

Using the LIDAR Analyst classification default settings, you can quickly classify your point cloud into ground, buildings, and vegetation classes. Once classified, you can view a summary of the classification statistics for each classification type. However, you will need a 3D or 2D point viewer to visualize the classification.

To classify point cloud data:

1. From the LIDAR Analyst (on page 19) toolbar, select Extraction > Classify Point Cloud. The Point Cloud Classifier (on page 125) dialog displays.

Figure 69: Point Cloud Classifier

2. Verify that your bare earth layer (DEM_bareEarth1) displays in the bare earth field. The Open LAS File dialog displays.

3. Select the Ellipsis [...] button to the right of the Input LAS File field. The Open LAS File dialog displays.

4. Navigate to the LIDAR Analyst Tutorial dataset, and do the following:

Select Exercise 2.

Select the TO_core_last.las file, and then click Open.

The selected LAS file appears in the Input LAS File field.


Advanced Lesson

5. Verity the following:

Buildings - Verify that your DEM_buildings layer displays in this field. If necessary, select the correct buildings layer. LIDAR Analyst enters <none> in the Forests layer field, since there is no forest layer. When applicable, LIDAR Analyst automatically enters the trees layer in the Tree Points field.

Forests- Verify that your DEM_trees layer in this field. If necessary, select the correct Tree Points layer. The Map units box displays the map units selected for the bare earth extraction.

6. Click Reset to Defaults button. All settings reset to the default values.

7. Using the Classification Parameters in the center of the dialog box, you can control the height thresholds for the ground, buildings, and vegetation. In addition, you can choose to re-classify or maintain classes for points that were classified previously. Enter the following custom classification settings:

Select Ignore already classified points.

Ground height threshold field: 0.5 meters.

Building Settings

Minimum height field: 1.5 meters.

Search radius field: 2 meters

Minimum height for vegetation

Accept the default settings.

8. Click OK.

9. Navigate to C:\My_LA_Tutorial_Results\Lesson 2 and name the file DEM_classified.

The LIDAR Analyst process dialog box opens, displaying the progress of the point classifications. When complete, the LAS Classification Results dialog box opens, indicating that the LAS file classification was successful and displaying the Classification Statistics results.

10. Click Close.


Advanced Lesson

Reference: Lesson 2

In This Section

ArcMap Editor Toolbar............................................................... 100 ArcMap Tools Toolbar ............................................................... 100 ArcMap Zoom Tools .................................................................. 101 Bare Earth Extraction Dialog ..................................................... 101 Bare Earth Modification Settings Dialog .................................... 109 Building Extraction Dialog .......................................................... 111 Building Tool Settings Dialog ..................................................... 113 Create Bare Earth Modification Layer Dialog ............................. 118 Hierarchical Interpolate Dialog ................................................... 120 Hill-Shade and Relief Dialog ...................................................... 121 LAS File Selector Dialog ............................................................ 122 Overwatch Progress Window .................................................... 124 Point Cloud File Classifier Dialog .............................................. 125 Point Cloud to Raster Dialog ..................................................... 127 Process Bare Earth Modifications Dialog ................................... 129 Square up Buildings Dialog ....................................................... 132 Tree Extraction Dialog ............................................................... 134


Chapter 5

ArcMap Editor Toolbar

The ArcMap Editing toolbar is frequently used to start and stop editing mode when working with features and graphics. Refer to the ArcMap documentation for information about these tools.

Access Location:

ArcMap 10 and 10.1

Toolbar: Editor

Figure 70: ArcMap Editor Toolbar

ArcMap Tools Toolbar

The ArcMap Tools toolbar is frequently used for the Zoom tools. Refer to the ArcMap documentation for information about these tools.

Figure 71: ArcMap Tools Toolbar


Advanced Lesson

ArcMap Zoom Tools

The ArcMap Zoom tools are used to adjust features. The ArcMap editing keyboard shortcuts for zooming in (z), zooming out (x), and panning (c) are available when working with the ArcMap Create Features tool.

Figure 72: ArcMap Zoom Tools


The Bare Earth Extraction dialog is used to create and configure bare earth settings. You can specify returns, map units, extraction, as well as pre and post processing options.

Access Location:

LIDAR Analyst



Command: Extract Bare Earth

Doc Id: 9806



Chapter 5


Single/last return

Select a single/last return file from the drop-down menu or launch the LAS File Selector dialog.

First return

Select a first return file from the drop-down menu or launch the LAS File Selector dialog.

Map Units

Horizontal units

Allows you to choose the horizontal units for the bare earth extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Allows you to choose the vertical units for the bare earth extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Output Resolution (Point clouds only)


If extracting bare earth from LIDAR point clouds, choose this option to manually specify the cell size of the output bare earth in map units. You should select this option if you already know the native point spacing of the input point clouds or if you want to output a bare earth at a different resolution than the point spacing of your input point clouds.

Estimate Cell Size

If extracting bare earth from LIDAR point clouds, choose this option to allow LIDAR Analyst to automatically detect the point spacing of the LIDAR point clouds. This information is used by LIDAR Analyst to set the cell size of the output bare earth raster.

Bare Earth Extraction Method

Method 1: Rasters or Point Clouds

Select this option to find ground points that are not close to non-ground objects, such as buildings and trees.

Method 2: Point Clouds

Select this option for extracting bare earth from LAS point clouds. This option works well on just about any LAS point cloud but especially well on dense forests. Selected by default.

Use existing ground points are used if this option is checked.

Pre-process

Auto-detect no-data regions



Advanced Lesson

Remove spikes and pits before processing

Selecting this option enables the search and removal of spikes and pits caused by anomalies in the input DEMs. Use this option only if the LIDAR data was not cleaned by the vendor. It is better to run this process as a separate, post-processing option, where you have more control over the removal parameters. By default, this option is not selected.

Note: If you know that your data does not have any large flat regions, clear this option to speed up processing time.

Post-process

Remove negative nDSM regions

Since the extracted bare earth layer is an estimate of the bare-ground with features removed, it can lead to a normalized Digital Surface Model (nDSM) with negative values. The negative nDSM value corresponds to an area where the extractor estimated the bare earth surface to be higher than the actual surface height. These regions can therefore be safely set to the actual DEM height. A flattened DEM model is obtained using the formula: nDSM = DEM – bare earth.

Selecting this option results in all nDSM regions being replaced with last-return DEM values, thus setting those regions to an nDSM value of zero. If, after running a preliminary bare earth extraction, you find large height variations in your bare earth, you can try selecting this option and running your bare earth extraction again. By default, this option is not selected.

Smooth bare earth using low-pass filter; removes cars, shrubs, and low height objects


Bare earth output

Displays the output location for the bare earth extraction.

Reset to defaults

Resets all bare earth extractions to the default settings.

More

Expands the dialog to include more advanced bare earth extraction options.

Run Visible Extent

Runs as specified.

Preview

Allows you to preview the bare earth extraction with the chosen settings.


Chapter 5


The Bare Earth Extraction dialog expands to show additional options.


Bare Earth Extraction (Expanded) Options

Tree and Forest Parameters (Method 1)

Minimum slope for tree regions

Regions of the DEM with a slope greater than this value will be considered tree regions. The default is 10 degrees.

Minimum texture for tree regions

Regions of the DEM with a texture greater than this value will be considered tree regions. Texture values are derived from the aspect of the last-return DEM. The default is 80 percent.

Minimum difference between returns for tree regions

Any pixel where the elevation difference between first and last returns is greater than this value will be considered a tree region. Note: Use only when you are processing both first-and last-return data. The default is 0.3 meters.

Minimum forest size

Tree regions with an area greater than this value will be considered forest. The default is 10,000 square meters.


Advanced Lesson

Sample 1 point in forest regions for every <value>

In forested areas, a ground point (an interpolation point) will be sampled from the lowest elevation value that occurs in a square of the defined area.

Use average slope for tree mask

Check this option with bare earth extraction method 1 selected to perform LIDAR Analyst’s 4.2 method 1 extraction. Uncheck this option with bare earth extraction method 1 selected to perform LIDAR Analyst’s 4.2 method 2 extraction.

Ground Parameters (Method 1)

Slope threshold for flat ground (maximum slope in flat/steep ground)


Maximum slope in flat ground


Maximum slope in steep ground

Regions with a rate of change in slope greater than the slope threshold for flat ground will be considered steep ground, as opposed to flat ground. Thresholds are used to classify the maximum slope in flat ground and the maximum slope in steep ground as ground. The default slope threshold is 78 degrees. The default maximum slope in flat ground is 55 degrees and the default maximum slope in steep ground is 10 degrees.

Minimum area for ground regions

Defines the minimum area of a ground region. Does not determine the minimum polygon size in the final ground mask. The default is 35,000 square meters.






Chapter 5

Return Parameters (Method 1)

Threshold difference between last return and ground surface estimate to ground mask

Defines the distance between the bare earth and the last-return (or single return) DEM. Regions with a distance lower than this threshold will be considered ground regions. The default is 0.1 meters.

Cleanup bare-earth (post-process)

Selecting this option applies a "noise" filter to the bare earth. The noise filter removes small imperfections, resulting in a smoother looking bare earth. Use the slider bar to set smoothness parameters. The further to the right (Less smooth) the slider is moved, the lower the effect of the filter, the fewer regions to which the filter is applied, and the fewer imperfections that will be removed.

Setup Interpolator

Allows you to choose either Hierarchical Spline Interpolator of ArcGIS Spline Interpolator as the interpolation method.












Interpolation

Hierarchical Spline Interpolator

The native interpolator in LIDAR Analyst is the Hierarchical Spline Interpolator.

ArcGIS Spline Interpolator

If you have ArcGIS Spatial Analyst installed and activated on your workstation, the additional interpolator, ArcGIS Spline Interpolator, appears in the list. The Hierarchical Spline Interpolator often works better on large datasets. However, you may need to experiment to see which option works better with your data.


Advanced Lesson













Chapter 5



Ground Parameters





Masking Tab - Bare Earth Extraction Dialog

The Masking tab located in the Bare Earth Extraction dialog (expanded view) is used to select layers to mask.

Figure 76: Masking Tab


Advanced Lesson

Bare Earth Modification Settings Dialog

The Bare Earth Modification Settings dialog can be used to verify layer you wish to edit. If needed, you can change the layers.

Access Location:

LIDAR Analyst

Toolbar: LIDAR Analyst Bare Earth

Command: Delete Points from Bare Earth

Doc Id: 9994

Figure 77: Bare Earth Modification Settings

Figure 78: Process Bare Earth Modifications Dialog


Chapter 5

Bare Earth Modification Settings Options

Ground Points Layer

Allows you to choose the ground points layer.

Ground Mask Layer

Allows you to choose the ground mask layer.

Ground Mask Edits

Allows you to choose the ground mask edits layer.

Refresh Layer Lists

Refreshes the layer lists is outside lists were added to the drop-down menus.


Advanced Lesson

Building Extraction Dialog The Building Extraction dialog is used to se building removal parameters when running an extraction. For example, you can specify that any buildings with an area more than 30 square meters be removed. In addition, you can remove buildings by minimum and maximum height, as well minimum and maximum roof slope. From this dialog, you can launch the Square-Up dialog.

Access Location:

LIDAR Analyst



Command: Extract Buildings

Doc Id: 10107

Figure 79: Building Extraction Dialog

There are two building extractions dialogs with the similar options.

Figure 80: Building Extraction- Expanded View


Chapter 5

Buildings Extraction Options

Bare earth


Single/last return


First return

Displays the First Return field.

Horizontal units

Displays the horizontal units for the buildings extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Displays the vertical units for the buildings extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Extraction Method

Method 1 – Use this raster-based option to extract buildings from the bare earth raster. This is the original building extraction algorithm.

Method 2 – If the bare earth was generated from a point cloud, use this option to extract buildings directly from that point cloud. This approach works especially well with small building footprints.

Building output

Displays the name for the building output for the building extraction.

Reset to defaults

Resets all building extraction settings to the default settings.

<< Less button

Hides the Method 1, Method 2, Post-Process, and Square-Up tabs.

>> More button

Shows the Method 1, Method 2, Post-Process, and Square-Up tab


Advanced Lesson

Building Tool Settings Dialog

The Building Tool Settings dialog is used to configure auto-split, reshape and reorient, and courtyard cleanup tools. These options are organized one three separate tabs.

Access Location:

LIDAR Analyst

Toolbar: LIDAR Analyst Building Edit

Commands: Building Edit Tool Options, Building Auto-Split, Building Reshape, Courtyard Cleanup. and Building

Reorient.

Figure 81: Building Tool Settings Dialog

Building Tool Settings Options

Bare earth

Sets the path to bare earth image.

Building layer

Displays the name of the selected building layer.

Refresh Layers

Refreshes all images and layers displayed to reflect the selected images and layers.

Show Settings

Expands to displays settings.

Single/last return

Displays the name of the selected single/last return image.

First return

Displays the name of the selected first return image.


Chapter 5

Building Auto-Split Tool Tab - Building Tool Settings

Figure 82: Building Auto-Split Tool Tab

Building Auto-Split Tab Options

Height Sensitivity - Enter a value between 1 and 100. Height sensitivity affects building differentiation based on roof line height differences. Increasing the sensitivity can help with classifying alleyways and courtyards, but it can also result in a single building being classified as two or more separate buildings. The default is 25.

Minimum Building Height - Minimum height in meters. The default is 2.2 meters.

Minimum Building Area - Minimum building aggregate in square meters. The default is 50 square meters.

Slope Threshold - Enter a value between 0 and 90 degrees. Helps determine the edge of individual buildings. Lowering the threshold can help separate rows or clusters of buildings, but can also cause poor results for buildings with curved or pitched roofs. The default is 80 degrees.

Automatically Square-up Buildings - Select this option to automatically square up features when using the Building Auto-Split Tool. Selected by default.

Smoothing Tolerance - Enter the number of meters a building vertex is allowed to move to smooth the building edges. Tolerance defines the maximum distance a point can move in relation to its neighboring vertices. Smoothing is accomplished with the Bezier Smoothing algorithm and is performed even if the buildings are not squared up. The default is 1 meter.

Squaring Tolerance - Enter the number of meters that the vertices of an edge can move when snapping a building edge vertical or horizontal. The default is 6 meters.

Consider adjoining features when computing orientation - Select this option to square up buildings according to the orientations of buildings immediately adjacent to it. Each group of buildings that share common edges is squared up to match the major orientation of the group.

No z-values - Applies no z-values to the polygons vertices.

Actual z-values - Attaches actual z-values to each vertex. This can result in lopsided polygons, if the elevation varies greatly from vertex to vertex.


Advanced Lesson

Min. z-value - Takes the minimum of the pixel z-values underlying the polygon and attaches that value to each vertex.

Max. z-value - Takes the maximum of the pixel z-values underlying the polygon and attaches that value to each vertex.

Mean z-value - Takes the mean of the pixel z-values underlying the polygon and attaches that value to each vertex. The default selection.

Building Reshape and Reorient Tools Tab - Building Tool Settings

Figure 83: Building Reshape and Reorient Tools Tab

Building Reshape and Reorient Tools Options




Region Grow Window Size - Enter a value in meters to match the size of the building to be extracted. The value entered, 100 for example, indicates a 100 meter by 100 meter window size surrounding the clicked point. If a particular building extraction is incomplete or contains artifact edges in illogical places, this is most likely due to the fact that the window size is too small. The default is 100 meters.

Grow region using existing building extent - When checked, the region grow window size is ignored and the outline of the existing building is re-extracted by looking only within the extent of the existing building. Not selected by default.

Building reorient direction - Enter an orientation, in degrees, east of North that defines the current major building orientation that all selected buildings will be reoriented to match. Valid values are between 0 and 180 degrees. Default value is 0.

Automatically Square up Features - Select this option to automatically square up features when using the Building Auto-Split Tool. Not selected by default.


Chapter 5

Smoothing Tolerance - Enter the number of meters a building vertex is allowed to move

to smooth the building edges. The tolerance defines the maximum distance a point can move in relation to its neighboring vertices. Smoothing is accomplished with the Bezier Smoothing algorithm and is performed even if the buildings are not squared up. The default is 1 meter.




Min. z-values - Takes the minimum of the pixel z-values underlying the polygon and attaches that value to each vertex.

Max. z-values - Takes the maximum of the pixel z-values underlying the polygon and attaches that value to each vertex.

Mean z-values - Takes the mean of the pixel z-values underlying the polygon and attaches that value to each vertex. The default selection.

Courtyard Cleanup Tool Tab - Building Tool Settings


Courtyard Cleanup Options


Minimum Building Height - The minimum height in meters. The default is 2.2 meters.

Minimum Courtyard Area - The minimum courtyard size in square meters that should be removed. If no courtyards are being removed from the shape, first try increasing the Height Sensitivity. If that doesn't work, then decrease the minimum courtyard area. The default is 30 square meters.


Advanced Lesson

Weed out Foliage - Select to eliminate tall trees within the courtyard that will interfere with the extraction. Use when trees can mistakenly be considered part of the building. Only available when a first return is specified, since the first return will provide the most accurate depiction of trees present. The default is selected.

Force Courtyard Removal - Select to automatically delineate courtyards. The system uses height-clustering to determine the lowest area(s) of a building to be removed. This guarantees that a courtyard will be found and removed from any building polygon you select. The only exceptions are small courtyards that are less than the specified minimum courtyard area. The default is selected.

Texture Variety Threshold - Used in conjunction with Weed out foliage to define how varied the height values within an area have to be before it will be classified as a tree region. The higher the threshold, the more varied an area has to be before it is classified as a tree region. The default is 80.

Automatically Square up Features - Select to automatically square up features when using the Building Auto-Split Tool. The default is selected.

Smoothing Tolerance - Enter the number of meters a building vertex is allowed to move to smooth the building edges. The tolerance defines the maximum distance a point can move in relation to its neighboring vertices. Smoothing is accomplished with the Bezier Smoothing algorithm and is performed even if the buildings are not squared up. The default is 1 meter.








Chapter 5

Create Bare Earth Modification Layer Dialog

The Bare Earth Modification Layer dialog is used to configure new layers for correcting distortions and other problems.

Access Location:

LIDAR Analyst


Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Clean-up

Doc Id: 10194

Figure 85: Create Bare Earth Modification Layer

Related Procedures

Reference Guide:

Bare Earth Cleanup Chapter - Creating a Bare Earth Modification Layer

Create Bare Earth Modification Layer Options

Bare earth

Allows you to choose the bare earth file for the bare earth modification layer.

Single/last return

Displays the selected single/last return image.

First return

Displays the selected first return image.

Horizontal units

Allows you to choose the horizontal units for creating the modification layer including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.


Advanced Lesson

Vertical units

Allows you to choose the vertical units for creating the modification layer including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Ground points

Displays the ground points layer.

Ground mask

Displays the ground mask layer.

Ground points save path

The ellipsis button launches the Save Feature Data dialog opens. LIDAR Analyst provides a file name based on the name of the original bare earth with the process, which is displayed in the Ground points save path field.

Ground mask save path

The ellipsis button launches the Save Feature Data dialog opens. LIDAR Analyst provides a file name based on the name of the original bare earth with the process, which is displayed in the Ground mask save path field.

Ground mask edits save path

The ellipsis button launches the Save Feature Data dialog opens. LIDAR Analyst provides a file name based on the name of the original bare earth with the process, which is displayed in the Ground mask edits save path field.


Chapter 5

Hierarchical Interpolate Dialog

The Hierarchical Interpolator is used to set number of points, spline tension, and percentage when performing an extraction.

Access Location:

LIDAR Analyst

Dialog: Bare Earth Extraction

Command: Setup-Up Interpolator

Doc Id: 9811

Figure 86: Hierarchical Interpolator

Hierarchical Interpolate Options

Number of points for interpolation

Defines the size of regions within which interpolation will occur. The default is 300.

Spline tension

Defines the tension to use on the spline. The higher the value, the more rigid the spline will behave—the output surface will act like a thin piece of tin. Lower values will make the output surface act like a rubber sheet. The default is 0, indicating there is no-spline tension. The default setting works best in most situations. For steep, rugged terrain, use a higher setting, such as 50.

Percentage overlap

Defines the size of the overlap between regions. Interpolation is performed on each of the regions separately and then blended together into the final output surface. The default is 0.1.


Advanced Lesson

Hill-Shade and Relief Dialog

The Hill-Shade and Relief dialog is where you configure lighting, shadow and map units.

Access Location:

LIDAR Analyst

Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Analysis


Command: Create Hill-Shaded Image

Doc Id: 9918


Hill-Shade and Relief Options

Lighting altitude

Allows you to set the lighting altitude. Altitude is the slope or angle of the illumination source above the horizon. The units are in degrees, from 0 (on the horizon) to 90 degrees (overhead). The default is 45 degrees.

Lighting azimuth

Allows you to set the lighting azimuth. Azimuth is the angular direction of the sun, measured from north, in clockwise degrees from 0 to 360. An azimuth of 90 is east. The default is 315 degrees.

Compute shadow

When selected, provides additional visualization.

Shading Styles

Elevation #1

The default for interpolating to raster.

Elevation #2

Use this option on the second file when you want to display both first and LAS (Point Cloud) returns and be able to distinguish between the two.

Note: Elevation #1 and Elevation #2 are best used to represent first and last return DEMs,

respectively.


Chapter 5

Bare earth

Use this option for the extracted bare earth. Creates an RGB hill-shaded image with a specific color-map.

Full spectrum

Use this option for creating an RGB hill-shaded image with the full color map range.

Partial spectrum

Use this option for creating an RGB hill-shaded image with a partial color map range.

Relief only

Use this option for creating a shaded (relief) gray-scale image that has a 3D appearance.

Map Units

Horizontal units

Allows you to choose the units of measurement for the horizontal units.

Vertical units

Allows you to choose the units of measurement for the vertical units.

LAS File Selector Dialog

The LAS File Selector is used to review LAS File information by setting the file path and filter option. Once the file is selected, you can expand the dialog to view header information and filter results by return.

Access Location:

LIDAR Analyst

Dialog: Point Cloud to Raster with Filtering or Point Cloud to Multiple Rasters

Figure 88: LAS File Selector Dialog

LAS Selector Options

File path

Displays the file path of the LAS file.

Filter by

Sets the filter to First Return, LAS Return, All Returns, or Custom Returns.

More

Expands the LAS File Selector (on page 123) dialog and displays the LAS file information for the selected file.


Advanced Lesson

LAS File Selector - Expanded View

Figure 89: LAS File Selector Expanded

LAS File Selector - Expanded View Options

Filter by

Selected option displays in the Return Filter matrix under Filter Properties.

First Return - Filter by First Return if you want to create a raster image containing first return information.

LAS Return - Filter by LAS Return to create a raster image containing LAS return information.

All Returns - Filter by All Returns to create a raster image containing information from all points. Also, select All Returns if your return information is not organized by first and LAS returns or if you intend on creating an Intensity raster.

Coordinate System

Displays the coordinate system information.

LAS Header Information

Displays information about the file. You can determine if first and/or last points are identified in your data. For example, your data may include the following:

Return Filter

Corresponds to the return Information matrix in the header.


Chapter 5

Include Options

Synthetic

Refers to points that were added manually to a point cloud, i.e., points not acquired by the sensor.

Key-Point

Refers to geo-referenced control points in the point cloud. Key-points cannot be moved or deleted. They were either captured via LAS or added manually to the dataset.

Withheld

Refers to points that are inaccurate due to noise. They are kept in the point cloud data with a Withheld label. They will not be used for data interpolation or analysis.

Edge of Flightline

Refers to points that were acquired on the edges of the flightlines. Depending on the precision of the equipment used, these points may contain inaccuracies.

Overwatch Progress Window

The Overwatch Progress Windows shows the status after most operations. The information reported varies depending on the task initiated. The window looks similar to the following:

Figure 90: Overwatch Progress Window


Advanced Lesson

Point Cloud File Classifier Dialog

The Point Cloud Classifier dialog is used to classify points once you have extracted your bare earth, buildings, and vegetation features.

Access Location:

LIDAR Analyst



Command: Classify Point Cloud

Doc Id: 10321

Figure 91: Point Cloud Classifier

Point Cloud File Classifier Options

Single/last return


First return


Bare earth

Allows you to choose the bare earth file.

Input LAS file

Buildings

Display the selected buildings image.

Forests

Display the selected forests image.

Tree points

Display the selected tree points image.


Chapter 5

Horizontal units

Sets the horizontal units including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Sets the vertical units including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Ignore already classified points

Select this option to maintain classes already assigned to points. If cleared, the classifier will reclassify points that were previously categorized.

Ground height threshold

Points that fall within this value of the bare ground (in the bare earth extraction) will be classified as ground. Default is 0.2 meters.

Minimum height

Points with a height of at least this value above the bare ground that fall within a building polygon will be classified as a building (if not classified as ground). Points classified as ground or buildings will not be considered for vegetation. The default is 2.2 meters.

Search radius

Defines the buffer to apply around a building when classifying the LAS points. The default is 1 meter.

Low vegetation

Low-lying vegetation, such as shrubs, with a height of at least this value. Using 0.3 meter, points that are greater than or equal to 0.3 meter in height and less than 1 meter will be categorized as Low vegetation. The default is 0.3 meter.

Medium vegetation

Mid-sized vegetation, such as shrubs and immature trees, with a height of at least this value. Using 1 meter, points that are greater than or equal to 1 meter in height and less than 2 meters will be categorized as Medium vegetation. The default is 1 meter.

High vegetation

Tall vegetation, such as mature trees, with a height of at least this value. Using 2 meters, points that are greater than or equal to 2 meters in height will fall into the High vegetation class. The default is 2 meters.

Reset to defaults

Resets all LAS file classifier settings to the default settings.


Advanced Lesson

Point Cloud to Raster Dialog

The Point Cloud to Raster dialog is where interpolation, raster properties, and cell size are configured. You can also set column and row raster properties.

Access Location:

LIDAR Analyst


Command: Point Cloud to Raster with Filtering

Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Point Cloud Tools

Doc Id: 9915

Figure 92: Point Cloud to Raster

Related Procedures:

Reference Guide:

Point Cloud Data Chapter - Selecting a Point Cloud File to Convert to Raster

Point Cloud to Raster Options

Input file

Displays the name of the selected file to be converted.

Interpolation field

Allows you to select Elevation to create a raster DEM for the input LAS file, or Intensity to create an intensity raster from the LAS file.

Elevation - Creates a raster DEM for the input LAS file.

Intensity - Creates an intensity raster from the LAS file. The Intensity (Int) field displays under Extents Information in the LAS header. If a dataset does not contain intensity values, you cannot create an intensity raster.


Chapter 5

Fill holes in data

Selecting this option will fill any regions containing no LAS points with an interpolated surface. In most cases, you will not want these regions to be filled with a surface. Typically, holes occur in LAS files due to the non-existence of data (holes can occur due to water features, bad data, shadow regions, or removal of points). Since holes are defined by their occurrence within the convex hull of the entire dataset, (i.e., there are points surrounding the hole in all directions), they can only be filled in reliably if they are small. If the holes are large, you can get interpolation artifacts as a result of the distance of the points used to fill in the holes.

Set output raster properties from input LAS file

Set output raster properties from template raster

Allows you go choose template from a list.


When selected, allows you to manually specify the cell size as opposed to using the default cell size.

X cell size

Reflects the X cell size of the point spacing you enter.

Y cell size

Reflects the Y cell size of the point spacing you enter.

Note: The X and Y values are the same as the point spacing value for the LAS file data. The fields are automatically updated with the value entered in the point spacing field on the LAS File Selector (on page 123) dialog.

Number of columns

Displays the number of columns for the output raster dataset.

Number of rows

Displays the number of rows for the output raster dataset.


Advanced Lesson

Process Bare Earth Modifications Dialog

The Process Bare Earth Modifications dialog is used to configure and process a bare earth modification layer after you have identified points to add or delete.

Access Location:

LIDAR Analyst


Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Clean-up

Doc Id: 9995

Figure 93: Process Bare Earth Modifications

Related Procedures

Reference Guide:

Cleanup Bare Earth Results Chapter - Creating a Bare Earth Modification Layer

Process Bare Earth Modifications Options

Bare earth

Allows you to choose the bare earth file for the bare earth modification layer.

Single/last return


First return


Ground points

Displays the ground points layer.

Ground mask

Displays the ground mask layer.


Chapter 5

Ground mask edits

Displays the ground mask edits layer.

Horizontal units

Allows you to choose the horizontal units for the bare earth modification including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Allows you to choose the vertical units for the bare earth modification including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Auto-detect no-data regions (pre-process)


Remove spikes and pits before processing (pre-process)

Selecting this option enables a search for and the removal of spikes and pits caused by anomalies in the input DEMs. Use this option only if the LIDAR data was not cleaned by the vendor. It is better to run this process as a separate, post-processing option, where you will have more control over the removal parameters. By default, this option is not selected.

Remove negative nDSM regions (post-process)

Since the extracted bare earth layer is an estimate of the bare-ground with features removed, it can lead to a normalized Digital Surface Model (nDSM) with negative values. The negative nDSM value corresponds to an area where the extractor estimated the bare earth surface to be higher than the actual surface height. These regions can therefore be safely set to the actual DEM height. A flattened DEM model is obtained using the formula: nDSM = DEM – bare earth. Selecting this option results in all nDSM regions being replaced with last-return DEM values, thus setting those regions to an nDSM value of zero. If you find large height variations in your bare earth, you can try selecting this option and running your bare earth extraction again. By default, this option is not selected.

Smooth bare earth using low-pass filter (post-process) removes cars, shrubs, and low height objects


Bare earth output

Displays the output location for the bare earth modification.

Reset to defaults

Resets all bare earth modification settings to the default settings.

More

Expands the dialog box to include more advanced bare earth modification options.


Advanced Lesson

Output last return if elevation difference between last return and ground surface estimate is - If the distance between the last-return (or single return) DEM and the extracted bare earth is lower than this threshold, than that region will be replaced with values from the last-return DEM. This step adds fidelity to the extracted bare earth. If this value is set to 0, then the output bare earth will be the original interpolated bare earth with post-processing clean-up applied. The default is 0.5 meters.

Cleanup bare earth (post-process) - Selecting this option applies a "noise" filter to the bare earth. The noise filter removes small imperfections, resulting in a smoother looking bare earth. Used in conjunction with the More smooth/Less Smooth slider. Selected by default.

More smooth/Less smooth slider - If you select Cleanup bare earth, use the slider bar to set the smoothing tolerance. The slider determines how much noise to remove. The further to the right (Less smooth) the slider is moved, the lower the effect of the filter, the fewer regions to which the filter is applied, and the fewer imperfections that will be removed.


Chapter 5

Square up Buildings Dialog

The Square up Buildings dialog includes squaring up options for matching the polygon to the underlying building shape, using straight sides.

Access Location:

LIDAR Analyst

Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Enhancement > Square Up Buildings


Command: Square Up Building

Doc Id: 10302

Figure 94: Square Up Buildings

Square up Buildings Options

Bare earth

Allows you to choose the bare earth file.

Single/last return


First return



Advanced Lesson

Horizontal units

Allows you to choose the horizontal units for squaring up buildings including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Allows you to choose the vertical units for squaring up buildings including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Real-Time Preview

Fills selected polygons with specified color or adds vertices to selected lines.

Smoothing Tolerance

Enter the number of meters a building vertex is allowed to move to smooth the building edges. Tolerance defines the maximum distance a point can move in relation to its neighboring vertices. This function is the same as the one found in the Buildings Extraction window. Values entered in either one will be reflected in the other. Smoothing is accomplished with the Bezier Smoothing algorithm. The default is 1 meter.

Squaring Tolerance

Sets the number of meters that the vertices of an edge can move when snapping the edge vertical or horizontal. The default is 6 meters.

Consider all likely feature orientations when squaring up

Attempts many likely orientations and squares up features using the orientation that provides the best results. Selected by default.

Fine-tune rotation

Fine-tunes the orientation angle of the polygon by the specified number of degrees. The default value is 0 degrees.

Consider adjoining features when computing orientation

Takes into account the orientation of adjoining features when squaring each feature. Not selected by default.

Z-enable buildings using

Allows you to choose the z-value setting including No z-value, Actual z-value, Min. z-value, Max. z-value, and Mean z-value.


Chapter 5

Tree Extraction Dialog

The Tree Extraction dialog is used to specify tree and forest extraction settings. You can optimize results for dense forests or more accurate crown widths.

Access Location:

LIDAR Analyst



Command: Extract Trees

Doc Id: 10130


Tree Extraction Options

Bare earth


Single/last return


First return

Displays in the First Return field.

Buildings

Sets the buildings file used in the tree extraction.


Advanced Lesson

Horizontal units

Sets the horizontal units for the tree extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.

Vertical units

Sets the vertical units for the tree extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.

Method 1: Fixed window search

Extraction method for the tree extraction process (better for dense forests).

Method 2: Variable window search

Extraction method for the tree extraction process (better at getting accurate crown widths).

Figure 96: Tree Extraction Process Diagram

Note: Forest parameters are not available unless you select the Forest option at the bottom of the

dialog and designate a file output

Predominant tree/forest type

Set the predominant tree/forest type to match the type of trees present in the data. If most of the trees are either deciduous or coniferous, then select the corresponding tree type option. Select ‘Mixed’ if the data contain a blend of deciduous and coniferous trees. Select ‘Deciduous’ or ‘Coniferous’ if the data is mostly one type of tree. Selecting the appropriate type increases the accuracy of the tree extraction and attribution. The default setting is "Mixed".

Minimum tree height

Enter the minimum tree height to extract. The minimum tree height determines the minimum height a potential tree point has to have in order to be classified as a tree. Set this value appropriately for the data being processed. The minimum tree height is measured from the highest point of the tree crown to the ground (the length between A and C in the above diagram). The default is 3 meters.


Chapter 5

Maximum tree height

Enter the maximum tree height to extract. The maximum tree height determines the maximum height a potential tree point has to have in order to be classified as a tree. Set this value appropriately for the data being processed. The maximum tree height is measured from the highest point of the tree crown to the ground.

Typical tree height

Enter the average height of the tree to extract that is representative of the height of the trees you want to extract. Height is measured at the highest point of the tree crown, from (A) to (C) in the diagram above. It should be noted that setting the value too high will decrease the number of tree points extracted. The default is 40 meters.

Minimum size of a forest

Enter the minimum forest size that LIDAR Analyst should extract in a forest extraction. Available only when the Output forest areas option is selected. Determines how large of an area an extracted forest has to cover in order to be kept in the final output. The default is 600 square meters.

Tree points

Select Tree Points to return a point vector file showing individual trees. The default is selected.

Forest areas

Select to return a polygon vector file showing trees grouped together in forests or stands. When selected the Minimum size of a forest, becomes available. The default is selected.

Reset to defaults

Resets all tree extraction settings to the default settings.


Appendix A

LIDAR Analyst Tools

In this Section

LIDAR Analyst Toolbars ............................................................ 137


The most commonly used features and functions are accessed from the LIDAR Analyst toolbars. These toolbars are available once the LIDAR Analyst is installed and activated as an optional extension in ArcMap.

There are four toolbars:


LIDAR Analyst 3D Viewer



The 3D Viewer is an optional feature when installing LIDAR Analyst.

There is also the following optional toolbars.

Distributed Processing Toolbar is an optional toolbar that is available when the Distributed Processing toolkit is installed. Please contact Overwatch for more information about this option.

LIDAR Analyst also includes additional tools that can be added to the toolbar. You can create new toolbar with favorite options or simply add more tools to an existing toolbar.



LIDAR Analyst Menus

The LIDAR Analyst menu on the LIDAR Analyst toolbar provides access to common and advanced functions of the software.

Figure 97: LIDAR Analyst Menu

Each of the nine commands on the LIDAR Analyst drop-down menu opens a submenu of associated functions.

In This Section

Point Cloud Tools Menu ............................................................ 140 Extraction Menu ........................................................................ 142 Clean-up Menu .......................................................................... 146 Enhancement Menu .................................................................. 148 Analysis Menu ........................................................................... 150 Feature Modeler Menu .............................................................. 152 Licensing Menu ......................................................................... 153 Settings Menu ........................................................................... 154 Help Menu ................................................................................. 155

140 | LIDAR Analyst Tools

Appendix A

Point Cloud Tools Menu

The Point Cloud Tools menu provides seven commands for working with LAS files, including converting text files to LAS files and LAS files into raster images.

Figure 98: Point Cloud Tools Menu

Point Cloud to Raster with Filtering Point Cloud to Raster with Filtering is used to convert your point cloud dataset into a raster image. The resulting visual representation of your point-cloud data will help you reference features prior to extraction and especially during cleanup of your bare earth layer.

Access Location:

Toolbar: LIDAR Analyst Default

Menu: LIDAR Analyst > Point Cloud Tools

See also, Converting Point Cloud Files to Rasters in the LIDAR Analyst Reference Guide.

Point Cloud to Multiple Rasters Point Cloud to Multiple Rasters is used to convert your point cloud dataset into the most commonly used raster images. The Convert LAS File to Multiple Rasters dialog opens, allowing you to extract the first return, last return, and intensity rasters from a single point cloud dataset.

Access Location:


View LAS Header

Choose View LAS Header to view the LAS file header and statistical information generated by LIDAR Analyst in the LAS File Information dialog.

Access Location:




Text to Point Cloud

Text to Point Cloud is used to convert the text file to a Point Cloud format that can be used by LIDAR Analyst.

Access Location:


Convert Point Shapefile to Point Cloud

If your point cloud data is in shapefile format, you need to convert it to a Point Cloud file to work with it in LIDAR Analyst. To use this tool, the target shapefile must be in your table of contents.

Access Location:


Crop Point Cloud

To save processing time while experimenting with different settings, you can crop out a rectangular portion of a point cloud.

Access Location:


Set Coordinate System

Set Coordinate System is used to assign a coordinate system based on the LAS input file.

Access Location:

Menu: (LIDAR Analyst Toolbar) LIDAR Analyst > Point Cloud Tools

Apply Coordinate System

Apply Coordinate System is used to assign a different coordinate system based on the LAS input file. No points are transformed to the new coordinate system.

Access Location:



Appendix A

Extraction Menu

The Extraction Tools menu opens to provide you with three options for extracting specific data from your LIDAR DEMs, a command for classifying LAS points, Batch Processing, and Project Tools submenu option. It also includes Distributed Batch Processing and associated tools.

Figure 99: Extraction Menu

Extract Bare Earth/Bare Earth Extraction

Choose Extract Bare Earth to extract a bare earth surface from your LIDAR data. The Bare Earth Extraction dialog box opens, allowing you to enter your bare earth extraction parameters.

Access Location:


Menu: LIDAR Analyst > Extraction

Extract Buildings

Extract Buildings is used to extract buildings from your LIDAR data. The Buildings Extraction dialog box opens, allowing you to set your building extraction parameters.

Access Location:





Extract Trees

Choose Extract Trees to extract individual trees or forest stands from your LIDAR data. The Trees Extraction dialog box opens, allowing you to set your tree extraction parameters.

Access Location:



Classify Point Cloud

Choose this command to classify Point Cloud points. Three classes will be automatically extracted from the LAS file: ground, buildings, and vegetation. Vegetation can be divided into three size-based classes (low, medium, and high). You must extract bare earth, building, and trees/forests from your point cloud data before classifying your LAS points, and the extracted layers must be in the active data frame in your ArcGIS table of contents.

Access Location:


Extract Contour Lines

Choose Extract Contour Lines on bare earth results. Contour lines join points of equal elevation, enabling you to infer the steepness of the terrain.

Access Location:


Batch Processing

The Batch processing feature allows you to use the AFE model developed for one image to extract similar features from other images with the same spatial referencing, resolution, and point spacing.

Access Location:


Project Tools

Choose Project Tools to open a submenu providing additional tools for importing and repairing existing project files.


Appendix A

Import Bare Earth

If you want to run extractions on bare earth DEMs generated in previous versions of LIDAR Analyst or other applications, you can choose Import Bare Earth to associate the bare earth DEM with the input DEM rasters or LAS files.

Access Location:

Menu: LIDAR Analyst > Extraction > Project Tools

Repair Bare Earth

If the association between the files created together in a bare earth extraction is broken, choose Repair Bare Earth to repair the bare earth project file.

Access Location:


Align Elevation Data

If you have an existing bare earth DEM and the return DEMs don’t have quite the same extents as the bare earth DEM, then choose the Align Elevation Data tool to crop your return DEMs so that they perfectly overlay the bare earth DEM. Once the images have been aligned, then the bare earth can be imported along with the aligned DEMs using the Import Bare Earth tool.

Access Location:

Toolbar: LIDAR Analyst Optional Tool


Distributed Batch

Choose Distributed Batch to access the Distributed Batch Processing, Create Data Tiles, and Merge Result Tiles tools.

Create Data Tiles

Opens the Create Data Tiles tool, which subsets large images into smaller ones according to prespecified sizes.

Distributed Batch Processing

Opens the Distributed Batch Processing tool, which allows batch jobs to be setup using multiple networked computers.

Merge Result Tiles

Opens the Merge Result Tiles tool, which merges previously tiled images or shapefiles (using the Create Data Tiles tool) into a single larger image.



Create Data Tile Tool

The Create Data Tile tool is used to designate portions (or tiles) of mosaicked images for processing on multiple computers prior to running a batch job.

Access Location:

Distributed Processing Toolkit - Toolkit is a separate installation.

Menu (Feature Analyst Toolbar): Feature Analyst > Learning > Distributed Batch

Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Extraction > Distributed Batch

Toolbar: Distributed Processing

Distributed Batch Processing

Opens the Distributed Batch Setup dialog, where you can setup using multiple networked computers.

Access Location:


Menu ( Toolbar): Feature Analyst > Learning > Distributed Batch



Merge Result Tiles

The Merge Result Tiles tool is used to merge together previously tiled images (using the Create Data Tiles tool) into a single, larger image.

Access Location:





Distributed Dashboard

Opens the Distributed Dashboard dialog where you can view and configure status.

Access Location:






Appendix A

Clean-up Menu

The Cleanup Tools menu provides six tools for cleaning up your initial result layers.

Figure 100: Clean-up Menu

Create LIDAR Modification Layer

Choose Create LIDAR Modifications Layer to create a polygon markup layer that you can use to specify DEM modifications. Once you have specified the modifications run the Process LIDAR Modifications function. This process can be used to modify your bare earth or your first and last return LIDAR images.

Access Location:

Menu: LIDAR Analyst > Clean-Up

Process LIDAR Modifications

Choose Process LIDAR Modifications to process the input DEM based upon changes to the modifications layer created using the Create LIDAR Modifications Layer command.

Access Location:




Create Bare Earth Modification Layer

Choose Create Bare Earth Modification Layer to create a modification layer containing the original ground points and the ground mask used to create the initial bare earth layer.

Access Location:


Note: This process can only be used to modify existing bare earth layers created with LIDAR

Analyst.

Process Bare Earth Modifications

Choose Process Bare Earth Modifications to process the modifications you made to the bare earth modifications layer created using the Create Bare Earth Modifications Layer command.

Access Location:


Spikes and Pits Removal

Choose Spikes and Pits Removal to remove anomalous pits and spikes from your bare earth results layer. The Spike and Pits Removal dialog box opens, allowing you to set the parameters for removing spikes and pits.

Access Location:


Place Buildings on Bare Earth

Choose Place Buildings on Bare Earth to open the Place Buildings on Bare Earth dialog box, allowing you to combine the extracted buildings layer and the bare earth layer.

Access Location:



Appendix A

Reinterpolate Hydrology

Reinterpolate Hydrology tool is used to smooth over water features with a flat elevation value while at the same time, preserving or accounting for elevation changes due to stream gradient and topography. It is also designed to smooth out anomalies in the bare earth and most importantly, to properly fill in NDV’s (no data values) which are common problem when using LIDAR data.

Access Location:


Menu: LIDAR Analyst > Clean-up

Enhancement Menu

The Enhancement menu provides four tools for enhancing and defining your results.

Figure 101: Enhancements Menu

Enhance Buildings

Choose Enhance Buildings to extract individual building components within the extracted buildings footprints.

Access Location:

Menu: LIDAR Analyst > Enhancement



Attribute Buildings

Choose Attribute Buildings to open the Attribute Buildings dialog box, allowing you to attach elevation attributes to the building features acquired from your LIDAR data.

Access Location:


Square up Buildings

Choose Square up Buildings to clean up your building result polygons. The Building Square Up dialog box opens, allowing you to enter your square up parameters.

Access Location:



Attribute Trees and Forests

Choose Attribute Trees and Forests to open the Attribute Trees and Forests dialog box, allowing you to attach elevation attributes to the vegetation acquired from your LIDAR data.

Access Location:



Appendix A

Analysis Menu

The Analysis Tools option provides access to nine analysis tools available in LIDAR Analyst.

Figure 102: Analysis Menu

Create Aspect Image

Choose Create Aspect Image to create an aspect image on the layer highlighted in the table of contents. Aspect identifies the direction of the steepest downward pointing slope.

Access Location:

Menu: LIDAR Analyst > Analysis

Create Slope Image

Choose Create Slope Image to create a slope image on the layer highlighted in the table of contents. Slope computes the maximum rate of change between a pixel and its neighbors. The value of slope ranges from 0 to 90 degrees.

Access Location:




Create Hill-Shade Image

Choose Create Hill-Shade Image to run the hill-shade process on the layer highlighted in the table of contents.

Access Location:


Toolbar: LIDAR Analyst default

Terrain Analysis

Choose Terrain Analysis to extract a mask image that satisfies certain user defined spatial characteristics such as slope, texture, aspect, etc.

Access Location:



Generate NDSM

Choose Generate NDSM to extract the normalized Digital Surface Model DEM. Analytically, the NDSM is akin to flattening the terrain and is used to determine the true heights of objects as opposed to the elevation of objects provided by the DEMs.

Access Location:


Export to Google Earth (KML)

Use the LIDAR Analyst Export to Google Earth feature to export your feature results to the KML file format. KML is a file format used to display geographic data in an Earth browser, such as Google Earth. The export settings allow you to specify the attributes, colors, and icons to display.

Access Location:



Reprojection

Choose Reprojection to open a submenu providing additional tools for modifying the spatial projections of input files.

Access Location:



Appendix A

Unprojected layer

Use the Unproject Layer tool to remove spatial projections from raster, vectors, and point cloud files. Only the projection is removed while retaining the underlying Geographic Coordinate System.

Access Location:

Menu: LIDAR Analyst > Analysis > Reprojection

Ellipsoid/Geoid Height Conversion

Use the Ellipsoid/Geoid Height Conversion tool to transform DEMs and point clouds from WGS84 ellipsoid height to geoid height or vice-versa.

Access Location:

Menu: LIDAR Analyst > Analysis > Reprojection

Feature Modeler Menu

The Feature Modeler option provides a direct access to working with AFE files and associated libraries.

Figure 103: Feature Modeler Menu

Feature Modeler

Opens the Feature Modeler window, allowing you to view AFE models created during LIDAR extractions, modify existing models, and run the models on new data. AFE models depict, step-by-step, all the processes used in LIDAR Analyst to complete the feature extraction.

Access Location:


Menu: LIDAR Analyst > Feature Modeler



Feature Modeler Library Browser

Allows you to use search criteria to find an AFE model in a library database to use to extract similar features from other similar images.

Access Location:


Feature Modeler Library Administrator

Allows you to add AFE models with identifying criteria to the library for use by analysts throughout your organization.

Access Location:


Licensing Menu

The Licensing option provides a direct link to the LIDAR Analyst Licensing features.

Figure 104: Licensing Menu

License Manager

Opens the LIDAR Analyst License Manager dialog. The License Manager authorizes your LIDAR Analyst software and provides status information about current licenses.

Access Location:

Menu: LIDAR Analyst > Licensing


Appendix A

Settings Menu

The Settings menu allows access to the Preferences tool, which provides options to set and edit LA toolbar settings affecting general behavior, cache settings, and message handling.

Figure 105: Settings Menu

Preferences

The Preferences tool opens the settings dialog box allowing you to modify and/or run several of the most common administrative registry settings and functions.

Access Location:

Menu: LIDAR Analyst > Settings



Help Menu

Help provides access to LIDAR Analyst assistance, including the Tutorial application and software documentation.

Figure 106: Help Menu

About LIDAR Analyst

Choose About LIDAR Analyst to open the LIDAR Analyst About dialog box. The About dialog provides information only regarding your version of LIDAR Analyst.

Access Location:

Menu: LIDAR Analyst > Help

Reference Manual

Choose Reference Manual to open the LIDAR Analyst Reference Manual. The Reference Manual provides explanations of each dialog box, button, and field available in the application, along with generalized instructions.

Access Location:

Menu: LIDAR Analyst > Help

Tutorial

Choose Tutorial to open the LIDAR Analyst Tutorial menu which provides you with the following options:

Access Location:

Menu: LIDAR Analyst > Help > Tutorial


Appendix A

Tutorial Document

Opens the LIDAR Analyst Tutorial application, providing a tutorial overview of the main aspects of the LIDAR Analyst program using prescribed datasets.

Access Location:


Tutorial Project

Opens the LIDAR Analyst Tutorial application, providing a tutorial overview of the main aspects of the LIDAR Analyst program using prescribed datasets.

Access Location:



The standard LIDAR Analyst toolbars open, by default, with the most commonly used tools. You can add or remove tool buttons to suit your needs.

Figure 107: LIDAR Analyst Toolbar

Point Cloud to Raster with Filtering

Point Cloud to Raster with Filtering is used to convert your point cloud dataset into a raster image. The resulting visual representation of your point-cloud data will help you reference features prior to extraction and especially during cleanup of your bare earth layer.

Access Location:



See also, Converting Point Cloud Files to Rasters in the LIDAR Analyst Reference Guide.



Extract Bare Earth/Bare Earth Extraction

Choose Extract Bare Earth to extract a bare earth surface from your LIDAR data. The Bare Earth Extraction dialog box opens, allowing you to enter your bare earth extraction parameters.

Access Location:



Extract Buildings

Extract Buildings is used to extract buildings from your LIDAR data. The Buildings Extraction dialog box opens, allowing you to set your building extraction parameters.

Access Location:



Extract Trees

Choose Extract Trees to extract individual trees or forest stands from your LIDAR data. The Trees Extraction dialog box opens, allowing you to set your tree extraction parameters.

Access Location:



Create Hill-Shade Image

Choose Create Hill-Shade Image to run the hill-shade process on the layer highlighted in the table of contents.

Access Location:



Terrain Analysis

Choose Terrain Analysis to extract a mask image that satisfies certain user defined spatial characteristics such as slope, texture, aspect, etc.

Access Location:




Appendix A

Export to Google Earth (KML)

Use the LIDAR Analyst Export to Google Earth feature to export your feature results to the KML file format. KML is a file format used to display geographic data in an Earth browser, such as Google Earth. The export settings allow you to specify the attributes, colors, and icons to display.

Access Location:



Feature Modeler

Opens the Feature Modeler window, allowing you to view AFE models created during LIDAR extractions, modify existing models, and run the models on new data. AFE models depict, step-by-step, all the processes used in LIDAR Analyst to complete the feature extraction.

Access Location:



Control Point Analyzer

This tool opens the Control Point Analyzer dialog box, allowing you to analyze differences in elevations between control data and DEMs. See Control Point Analysis for more information.

Access Location:


Crop Raster

Use to crop out a small section of a large image to run samples on before running processes on the entire image. This allows you to save processing time when experimenting with settings.

Access Location:


Open 3D View

Used to open a file or layer in the optional 3D Viewer. This viewer must be installed for this option to be enabled.

Access Location:




License Manager

Opens the GIS Analyst Suite License Manager.

Reinterpolate Hydrology

Reinterpolate Hydrology tool is used to smooth over water features with a flat elevation value while at the same time, preserving or accounting for elevation changes due to stream gradient and topography. It is also designed to smooth out anomalies in the bare earth and most importantly, to properly fill in NDV’s (no data values) which are common problem when using LIDAR data.

Access Location:


Menu: LIDAR Analyst > Clean-up


The Barth Earth toolbar provides tools for adding data points, removing ground clutter such as trees and buildings, reassigning, raising or lowering DEM heights, as well as replacing a DEM region.

Figure 108: LIDAR Analyst Bare Earth Toolbar

Add Points to Bare Earth Tool

Use this tool to alter the bare earth layer to show greater detail in the slope or rise of the landscape. This tool allows you to fix areas where the original extraction pass overly smoothed the result layer.

Access Location:

Toolbar: LIDAR Analyst Bare Earth Toolbar

Delete Points from Bare Earth Tool

Use this tool to remove non-bare earth features that are not represented by the other modification tools.

Access Location:



Appendix A

Remove Cars, Shrubs Tool

Use this tool to remove cars, low vegetations, and other low-height objects from the DEM.

Access Location:


Smooth Area Tool

Use this tool to smooth ragged DEM features. See Smoothing Bare Earth for more information.

Access Location:


Reassign DEM Height Tool

Use this tool to reassign the height of objects or areas within the DEM. See Reassigning DEM Height for more information.

Access Location:


Raise/Lower DEM Height Tool

Use this tool to raise or lower the height of an object or area within the DEM. See Raising or Lowering Feature Height for more information.

Access Location:


Replace DEM Region Tool

Use this tool to replace areas within the DEM with areas from the another DEM. See "Replacing an Area of the DEM" for more information.

Access Location:



The Building Edit toolbar provides tools for building settings, reshaping, cleanup, reorienting, squaring up, eroding, aggregating, smoothing features, and creating points in a building layer.

Figure 109: Building Edit Toolbar



Building Edit Tool Options

Use this tool to set parameter controls for the building edit tools. See "Setting Tool Parameters" for more information.

Access Location:


Building Auto-Split Tool

Select a single building or a group of buildings and use the tool to split each shape into multiple buildings. See "To Use the Building Auto-Split Tool" for more information.

Access Location:


Building Reshape Tool

Use this tool to manually edit building shapes. Holding down the SHIFT, CTRL, and ALT keys, or no key will result in different behavior for this tool. See the “Building Reshape and Reorient Tools” for more information.

Access Location:


Courtyard Cleanup Tool Use this tool to remove any areas of a building which are less than the minimum building height.

Access Location:


Building Reorient Tool

Use this tool to select multiple buildings at a time and then orient them to the same rotation angle. See "to reorient a building using the building reorient tool" for more information.

Access Location:


Square Up Buildings Tool

Choose Square Up Buildings to clean up your building result polygons. The Building Square Up dialog box opens, allowing you to enter your square up parameters.

Access Location:



Appendix A

Vector to Raster Tool

Converts a vector to a raster. The resolution is configured based on an existing raster layer. The input feature layer extent is configurable.

Access Location:


Raster to Vector

Converts a raster layer to vector. Cull setting in pixels can be configured for output in the Raster to Vector dialog.

Access Location:


Erode/Dilate Image Tool

Allows you to manipulate binary images. Use Erode to split apart features such as building polygons that are so close together they appear to bleed together. Use Dilate to join features together, like a disconnected network of roads or rivers. You must convert your vector result layer to an image layer before you can proceed with this task.

Access Location:


Customizing a Toolbar

You can customize the LIDAR Analyst toolbar with any or all of the LIDAR Analyst tools, including shortcut tool buttons associated with menu commands.

Note: All <product _name> functions can be added as a tool button to the toolbar.



Adding Tools to a Toolbar

For your convenience, you have the option of customizing the toolbar with specific tools/commands.

To add tools to a toolbar:

1. Right-click on the LIDAR Analyst (on page 19) toolbar or click the drop arrow, then choose Customize from the shortcut menu. The Customize dialog box opens.


2. Select the Commands tab. The Commands (on page 168) tab displays.

3. Select one of the following in the Commands list box:

LIDAR Analyst Commands

LIDAR Analyst Tools

Overwatch Commands

Overwatch Tools

4. Select the tool you want to add to the toolbar from the Commands list box.

5. Click and drag the tool to the LIDAR Analyst toolbar. Release the tool on the toolbar where you want it to appear. The tool appears on the toolbar in the location where you placed it.

6. Continue to drag and drop tools on the toolbar, as necessary.


Appendix A

7. To save your customized toolbar for use with the current project only, select the Options tab of

the Customize dialog. The Options tab displays.


8. Select Save all customizations to the document. The Save in Document dialog displays.

9. Choose OK to save the customizations to the current document.

10. To save the change to the base (normal.mxt) template, uncheck the Save all customizations to the document check box. This displays your customized toolbar in every new project you open.

11. Click Close.



Removing a Tool from a Toolbar

It is easy to remove any tool or command from a toolbar. The Customize dialog must be opened first before you can remove a tool.

To remove a tool from a toolbar:




The Customize (on page 166) dialog displays. All buttons on the toolbar activate.

2. Do one of the following:

Left-click the tool and select Delete from the shortcut menu.

Figure 112: Tool Shortcut Menu

Drag the tool off the toolbar and release the mouse.

Resetting a Toolbar

The toolbar settings can be reset to their default. You must open the Customize dialog to reset a toolbar.

To reset the LIDAR Analyst toolbar:




The Customize dialog displays.

2. Select the Toolbars tab. The Toolbar tab displays.

3. Select the appropriate toolbar in the Toolbars list, and click Reset. The toolbar resets to its default setting.


Appendix A

Customize Dialog

The Custom toolbar is used to create new toolbars and update existing toolbars.

Figure 113: Toolbars Tab



Toolbars Tab - Customize Dialog

The Toolbars tab on the Customize dialog allows you to choose which toolbars appear in the LIDAR viewing window.

Access Location:

ArcMap

Dialog: Customize

Right-click a toolbar or click the drop-arrow and select Customize from the shortcut menu.

Doc Id: 9537


Toolbar Tab Options

Toolbars

Displays a list of available to toolbars to display in the LIDAR viewing window.

New

Allows you to create a new custom toolbars with preferred tools.

Rename

Renames a toolbar.

Delete

Deletes the selected toolbar.

Reset

Resets the toolbar selected in the list box to its original settings.

Keyboard

Opens the Customize Keyboard dialog where you can create custom shortcuts.

Add from file

Allows you to add a toolbar from an existing file.


Appendix A

Commands Tab - Customize Dialog

The Commands tab on the Customize dialog allows you to choose specific tools to customize your toolbars.

Access Location:

ArcMap

Dialog: Customize


Figure 115: Commands Tab

Commands Tab Options

Categories

Displays the categories of commands.

Commands

Displays the commands available to customize toolbars.

Show commands containing

Allows you to search for specific commands with a keyword(s).

Description

Provides a description of the selected command.

Keyboard

Opens the Keyboard Shortcut dialog where you can add custom keyboard shortcuts.

Add from file

Allows you to add a command from an existing file.



Options Tab - Customize

The Options tab is where you can set icon size to large, show tooltips, save customizations to the document, and create new menus and toolbars.

Access Location:

ArcMap

Dialog: Customize




Appendix B

Point Cloud/LAS File Information

In this Section

LAS File Information .................................................................. 171

LAS File Information

It is important to review the LAS file information to become familiar with your data. LAS header information includes the number of points in the file; number of points by return; and scale, offsets, and extents information. You can also run an update on your LAS file to verify header information and review generated statistics. The updated LAS file statistics information includes approximate point spacing, return information, point statistics (numbers of edge points, synthetic points, key-points, and withheld points), and LAS classification information.

Reviewing LAS File Header and Statistics

You can view the LAS file header and statistical information generated by LIDAR Analyst in the LAS File Information dialog.

Vendor data-entry errors can result in incorrect header information. Incorrect header entries can range from the wrong number of points by return to the wrong extent information. If you think the header information contains errors, choose Update File Statistics on the LAS (Point Cloud) File Information dialog. LIDAR Analyst will parse the LAS (Point Cloud) file and display known file information in the lower box.

172 | Point Cloud/LAS File Information

Appendix B

To view the LAS file header:

1. From the LIDAR Analyst (on page 19) toolbar, choose LIDAR Analyst > Point Cloud Tools > View LAS Header. The LAS File Information (on page 171) dialog opens.

2. Click the Input File ellipsis […] button. The Open LIDAR File dialog opens.

Browse to the file location where your LIDAR data is stored. If working with the LIDAR Analyst

tutorial dataset, navigate to C:\Overwatch Tutorials\GAS\Arc-

GIS\LA_ArcGIS_Tutorial (or path where this is located on your system) and do the

following:

Select Exercise 2

Select TO_core_last.las file

3. Click Open. The selected file appears in the Input File field. The file header associated with the LAS file displays in the Data box.

Figure 117: LAS File Statistics

Note: It can take a while for LIDAR Analyst to Update File Statistics for large files.



To view LAS file statistics:

1. Once a file is loaded, click the Update File Statistics button to view statistics associated with your LAS file. LIDAR Analyst parses the file and displays the file information in the lower box of the LAS File Information dialog. It may take more time to show stats for large files.

2. When you are finished viewing the header and/or statistics, click OK. The LAS File Information dialog closes.

LAS Classification Statistics

LAS classification statistics will be included if the data points contain land use/land class information. Your points can be classified manually by the LIDAR vendor or by a GIS Analyst. If your point cloud has been classified, the details (class names and number of points per class) will be included under LAS Classification statistics. If your dataset is not classified, all points will be listed under “Number of points classified” as “Never Classified.”

LAS File Selector - Expanded View

Figure 118: LAS File Selector Expanded


Appendix B

LAS File Selector - Expanded View Options

Filter by

Selected option displays in the Return Filter matrix under Filter Properties.

First Return - Filter by First Return if you want to create a raster image containing first return information.

LAS Return - Filter by LAS Return to create a raster image containing LAS return information.

All Returns - Filter by All Returns to create a raster image containing information from all points. Also, select All Returns if your return information is not organized by first and LAS returns or if you intend on creating an Intensity raster.

Coordinate System

Displays the coordinate system information.

LAS Header Information

Displays information about the file. You can determine if first and/or last points are identified in your data. For example, your data may include the following:

Return Filter

Corresponds to the return Information matrix in the header.

Include Options

Synthetic

Refers to points that were added manually to a point cloud, i.e., points not acquired by the sensor.

Key-Point

Refers to geo-referenced control points in the point cloud. Key-points cannot be moved or deleted. They were either captured via LAS or added manually to the dataset.

Withheld

Refers to points that are inaccurate due to noise. They are kept in the point cloud data with a Withheld label. They will not be used for data interpolation or analysis.

Edge of Flightline

Refers to points that were acquired on the edges of the flightlines. Depending on the precision of the equipment used, these points may contain inaccuracies.



First and/or Last Return Points

First/Last Return Information Description

LAS File contains first and last returns.

Data includes valid first and last return points.

Select First Return or Last Return in the Filter By field

LAS File does not contain points that can be assigned to the traditional first and last return specification.

Last and first returns can be manually specified for this LAS file.

Points can be manually specified as first and last returns. Select All Returns in the Filter By field, or select Custom Return and define the points to be included under Filter Properties.

Do not select First Return or Last Return in the Filter by field.

LAS File does not contain points that can be assigned to first and last returns.

Points can only be classified as a single return. Select All Returns in the Filter By field.

Number of points with bad return info.

Data includes points with bad return numbers and the number of returns defined. Select All Returns in the Filter By field.

Evaluate your return data by examining the Return Information matrix.

Figure 119: Return Information Matrix

Sample Return Information Matrix, showing last return data in 1:1 and 2:2, and first return data in 1:1 and 1:2


Appendix B

Returns Matrix Description

First Returns Defined by the points in the first column of the matrix (i.e., [1,1], [1,2],[1,3],[1,4] and [1,5]). First Returns can have point data in any of the cells in Column 1 as long as there is corresponding point data in the columns to the right (indicating second through fifth returns).

Last Returns Defined by the points along the middle diagonal (i.e., [1,1],[2,2],[3,3],[4,4],[5,5]) of the matrix. Last Returns have point data in the cells along the diagonal.

Intermediate Returns Intermediate Returns point data to the right of the first return column and below the diagonal.

(*) symbol Data includes points with bad return numbers and the number of returns defined. Select All Returns in the Filter By field.

Total The Last row and the Last column contain the totals. The totals in the Last row correspond to the Number of points by return field in the LAS header.

Output Resolution

The output resolution is used to establish the cell size of your raster image (DEM). You should interpolate a raster DEM at or close to the actual point spacing of your point cloud data. Using an output resolution that is higher than the actual point spacing results in a loss of accuracy, and using an output resolution that is lower than the actual point spacing leads to wasted disk space and processing time (large files).

Typically the output resolution is the same in the x and y direction. If you know that this is not the case for your data, you can change the x cell spacing and y cell spacing independently. If you do not know the actual point spacing for your point cloud data, you can allow LIDAR Analyst to auto-detect it for you.



LAS Point Statistics

Option Definition

Synthetic Refers to points that were added manually to a point cloud, i.e., points not acquired by the sensor.

Key-Point Refers to geo-referenced control points in the point cloud. Keypoints cannot be moved or deleted. They were either captured via laser or added manually to the dataset.

Withheld Refers to points that are inaccurate due to noise. They are kept in the point cloud data with a Withheld label. They will not be used for data interpolation or analysis.

Edge of

Flightline

Refers to points that were acquired on the edges of the flightlines. Depending on the precision of the equipment used, these points may contain inaccuracies

Total The Last row and the Last column contain the totals. The totals in the Last row correspond to the Number of points by return field in the LAS header.


Appendix C

Building Edit Tools

In this Section

Using Building Edit Tools ........................................................... 179 Setting Tool Parameters ............................................................ 180 Setting the Building Auto-Split Tool Parameters ........................ 181 Setting the Building Reshape and Reorient Tool Parameters .... 181 Setting the Courtyard Cleanup Tool Parameters ....................... 182 Using the Building Auto-Split Tool ............................................. 183 Reference - Building Edit Tools ................................................. 185

Using Building Edit Tools

LIDAR Analyst includes the Building Edit (on page 20) toolbar, which includes four building editing tools for cleaning up your building layers and a tool for setting the options for each tool.

Using the LIDAR Analyst Building Edit Tools, you can automate the process of adjusting buildings or building features. To use the building edit tools, you must have an unmodified building layer loaded in the table of contents.

Building Edit Tool Options

Use this tool to set parameter controls for the building edit tools. See "Setting Tool Parameters" for more information.

Access Location:


180 | Building Edit Tools

Appendix C

Building Auto-Split Tool

Select a single building or a group of buildings and use the tool to split each shape into multiple buildings. See "To Use the Building Auto-Split Tool" for more information.

Access Location:


Building Reshape Tool

Use this tool to manually edit building shapes. Holding down the SHIFT, CTRL, and ALT keys, or no key will result in different behavior for this tool. See "The Building Reshape and Reorient Tools" for more information.

Access Location:


Courtyard Cleanup Tool

Use this tool to remove any areas of a building which are less than the minimum building height.

Access Location:


Building Reorient Tool

Use this tool to select multiple buildings at a time and then orient them to the same rotation angle. See "to reorient a building using the building reorient tool" for more information.

Access Location:


Setting Tool Parameters

Before you use the building edit tools, you must set the parameters for each tool function. The parameters are set for the three tools using the Building Edit Tool Options tool. The four editing tools are described later in this section.

To open the building tool settings dialog box:

1. Select the building layer in the table of contents.

2. From the ArcMap Editor (on page 24) toolbar, choose Editor > Start Editing.

3. Select the building layer as the editing target layer.


Setting the Building Auto-Split Tool Parameters

4. On the LIDAR Analyst Building Edit (on page 20) toolbar, choose Building Edit Tool Options

tool . The Building Tool Settings (on page 113) dialog box opens. When applicable, LIDAR Analyst detects and enters your bare earth layer in the Bare Earth field. The single/last return LIDAR image and the first return LIDAR image appear in their respective fields. If you are not using a First Return image, the field remains empty.

5. Verify that your bare earth layer displays in the Bare Earth field. If necessary, select the correct bare earth layer. The building layer appears in the Building Layer field.

6. Verify that the correct building layer displays in the Building Layer field.

7. Choose Show Settings. The dialog box expands to display the building tool options.

Setting the Building Auto-Split Tool Parameters

To set the building auto-split tool parameters:

1. Click the Building Auto-Split Tool tab on the Building Tool Settings dialog. The Building Auto-Split (on page 114) tab displays.

2. Review the default Building Auto-Split Tool settings.

Note: You can choose Reset to defaults at any time to return to the default settings.

3. Accept the default settings or set the options according to the following:

Note: For convenience, leave the Building Tool Settings dialog box open on your desktop to alter the tool parameters, as necessary, while you are editing.


Click the Close button in the top right corner to close the dialog box.

Choose another tab to continue setting tool options.

Setting the Building Reshape and Reorient Tool Parameters

To set the building reshape and reorient tool parameters:

1. Choose the Building Reshape and Reorient Tools tab on the Building Tool Settings dialog box. The Building Reshape and Reorient Tools (on page 115) tab displays.

2. Review the default Building Reshape and Reorient Tool settings.


3. Accept the default settings or set the options according to the following:

Note: For convenience, leave the Building Tool Settings dialog box open on your desktop to

alter the tool parameters, as necessary, while you are editing.


Choose the Close button in the top right corner to close the dialog box.



Appendix C

Setting the Courtyard Cleanup Tool Parameters

To set the courtyard cleanup tool parameters:

1. Choose the Courtyard Cleanup Tool tab on the Building Tool Settings dialog. The Courtyard Cleanup Tab Tool (on page 116) tab displays.

2. Review the default Courtyard Cleanup Tool settings.


3. Accept the default settings.

Note: For convenience, leave the Building Tool Settings dialog box open on your desktop to alter the tool parameters, as necessary, while you are editing.


Choose the Close button in the top right corner to close the dialog box.





You must set the options for the tool before you can use it.

To use the building auto-split tool:

1. If you are not already in edit mode, choose Editor > Start Editing from ArcMap Editor toolbar.

2. Choose the Building Auto-Split tool on the LIDAR Analyst Building Edit (on page 20) toolbar.

3. Draw a stretchy box over the building(s) you want to split.

Note: You can also split a building by clicking on it.

When you release the mouse button the system automatically splits the selected polygon(s). The system divides the selected building into multiple buildings, using the parameters entered in the Building Tool Settings dialog box.

Figure 120: Building Auto-Split Example

The same image before (A) and after (B) splitting the buildings.

4. When you are done editing buildings, save your edits.


Reference - Building Edit Tools


In This Section

Building Tool Settings Dialog ..................................................... 185

Building Tool Settings Dialog

The Building Tool Settings dialog is used to configure auto-split, reshape and reorient, and courtyard cleanup tools. These options are organized one three separate tabs.

Access Location:

LIDAR Analyst


Commands: Building Edit Tool Options, Building Auto-Split, Building Reshape, Courtyard Cleanup. and Building

Reorient.

Figure 121: Building Tool Settings Dialog


Appendix C

Building Tool Settings Options

Bare earth

Sets the path to bare earth image.

Building layer

Displays the name of the selected building layer.

Refresh Layers

Refreshes all images and layers displayed to reflect the selected images and layers.

Show Settings

Expands to displays settings.

Single/last return

Displays the name of the selected single/last return image.

First return

Displays the name of the selected first return image.

Building Auto-Split Tool Tab - Building Tool Settings

Figure 122: Building Auto-Split Tool Tab

Building Auto-Split Tab Options




Slope Threshold - Enter a value between 0 and 90 degrees. Helps determine the edge of individual buildings. Lowering the threshold can help separate rows or clusters of buildings, but can also cause poor results for buildings with curved or pitched roofs. The default is 80 degrees.



Automatically Square-up Buildings - Select this option to automatically square up features when using the Building Auto-Split Tool. Selected by default.

Smoothing Tolerance - Enter the number of meters a building vertex is allowed to move to smooth the building edges. Tolerance defines the maximum distance a point can move in relation to its neighboring vertices. Smoothing is accomplished with the Bezier Smoothing algorithm and is performed even if the buildings are not squared up. The default is 1 meter.


Consider adjoining features when computing orientation - Select this option to square up buildings according to the orientations of buildings immediately adjacent to it. Each group of buildings that share common edges is squared up to match the major orientation of the group.



Min. z-value - Takes the minimum of the pixel z-values underlying the polygon and attaches that value to each vertex.

Max. z-value - Takes the maximum of the pixel z-values underlying the polygon and attaches that value to each vertex.

Mean z-value - Takes the mean of the pixel z-values underlying the polygon and attaches that value to each vertex. The default selection.

Building Reshape and Reorient Tools Tab - Building Tool Settings

Figure 123: Building Reshape and Reorient Tools Tab


Appendix C

Building Reshape and Reorient Tools Options




Region Grow Window Size - Enter a value in meters to match the size of the building to be extracted. The value entered, 100 for example, indicates a 100 meter by 100 meter window size surrounding the clicked point. If a particular building extraction is incomplete or contains artifact edges in illogical places, this is most likely due to the fact that the window size is too small. The default is 100 meters.

Grow region using existing building extent - When checked, the region grow window size is ignored and the outline of the existing building is re-extracted by looking only within the extent of the existing building. Not selected by default.

Building reorient direction - Enter an orientation, in degrees, east of North that defines the current major building orientation that all selected buildings will be reoriented to match. Valid values are between 0 and 180 degrees. Default value is 0.

Automatically Square up Features - Select this option to automatically square up features when using the Building Auto-Split Tool. Not selected by default.










Courtyard Cleanup Tool Tab - Building Tool Settings


Courtyard Cleanup Options


Minimum Building Height - The minimum height in meters. The default is 2.2 meters.

Minimum Courtyard Area - The minimum courtyard size in square meters that should be removed. If no courtyards are being removed from the shape, first try increasing the Height Sensitivity. If that doesn't work, then decrease the minimum courtyard area. The default is 30 square meters.

Weed out Foliage - Select to eliminate tall trees within the courtyard that will interfere with the extraction. Use when trees can mistakenly be considered part of the building. Only available when a first return is specified, since the first return will provide the most accurate depiction of trees present. The default is selected.

Force Courtyard Removal - Select to automatically delineate courtyards. The system uses height-clustering to determine the lowest area(s) of a building to be removed. This guarantees that a courtyard will be found and removed from any building polygon you select. The only exceptions are small courtyards that are less than the specified minimum courtyard area. The default is selected.

Texture Variety Threshold - Used in conjunction with Weed out foliage to define how varied the height values within an area have to be before it will be classified as a tree region. The higher the threshold, the more varied an area has to be before it is classified as a tree region. The default is 80.

Automatically Square up Features - Select to automatically square up features when using the Building Auto-Split Tool. The default is selected.



Appendix C

Squaring Tolerance - Enter the number of meters that the vertices of an edge can move

when snapping a building edge vertical or horizontal. The default is 6 meters.







Appendix D

Building Reshape Tools

In this Section

Building Reshape Tool with the SHIFT Key ............................... 192 Building Reshape Tool with the CTRL Key ................................ 194 Building Reshape Tool with the ALT Key ................................... 195 Building Reshape Tool Alone .................................................... 196

192 | Building Reshape Tools

Appendix D

Building Reshape Tool with the SHIFT Key

Trimming Polygon Features

To trim an existing polygon feature construct your polygon that will be used to clip the existing polygon using the left mouse button to place vertices (A, B, C, D, & E). When you are about to place your last vertex (F), hold down the SHIFT key and double-click. This will place the final vertex (F) of the internal shape and execute a clip action. The system cuts the area inside the polygon you drew and closes the existing feature.

Figure 125: Trimming Polygon Features Example


Building Reshape Tool with the SHIFT Key

Cutting Holes in Polygons

To cut a polygon into multiple polygons, construct a polygon that bisects the existing polygon, using the left mouse button to place vertices (A, B, C). When you are about to place your final vertex (D) of the bisecting shape hold down the SHIFT key and double-click. This will place the final vertex (D) of the bisecting shape and execute a clip action. The system cuts the existing polygon, creating two polygons with the remaining vertices.

Figure 126: Cutting Holes in Polygons Example

Cutting a Polygon into Multiple Polygons

Holding down the SHIFT key, click to place the first vertex (A). Continue holding down the SHIFT key and place the remaining vertices (B, C & D). Double-click on D to close the polygon. The system cuts the existing polygon, creating two polygons with the remaining vertices.

Figure 127: Cutting a Polygon into Multiple Polygons Example


Appendix D

Building Reshape Tool with the CTRL Key

Closing Holes in Polygons

To close holes in polygons, simply hold down the CTRL key and left-click inside the polygon in which you want to close holes. The system closes all holes in the selected polygon with one click.

Figure 128: Closing Holes in Polygons Example

Creating New Polygons

To create a new polygon, select the building reshape tool. Hold down the CTRL key, and click in the center of the building you want to extract. The system creates a new building polygon, using the building settings in the Building Tool Settings dialog box.

Figure 129: Creating New Polygons Example


Building Reshape Tool with the ALT Key

Building Reshape Tool with the ALT Key

Splitting Polygon Features

To split a polygon, select the building reshape key and hold down the ALT key. Draw a line through a building polygon. The line must begin and end outside the polygon. Double-click to end the action. Make sure you continue to hold down the ALT key until you have double-clicked the mouse button. The system reshapes the polygon to match the cut you made, creating a second polygon.

Figure 130: Splitting Polygon Features Example


Appendix D

Building Reshape Tool Alone

Extending Polygon Feature

To extend a polygon feature, click to set the first vertex of your extension. Digitize a polygon. Continue to place vertices until you have drawn the shape you want. Double-click to close the polygon. The system redraws the lines of the existing polygon to include the area OUTSIDE the boundary of the existing polygon feature.

Figure 131: Extending Polygon Feature Example

Merging Polygon Feature

To merge the polygons, the shape you draw must overlap the edges of both features you want to merge. To merge polygon features, click to set the first vertex (A). Draw the stretchy line and click to set the next vertex. Continue placing vertices until you have drawn the shape you want. Double-click to place the last vertex (D). The system merges the polygons.

Figure 132: Merging Polygon Feature Example


Appendix E

Building Auto-Split Tools

In this Section

Splitting Buildings Using the Building Reshape Tool .................. 197 Adding to/Merging Buildings Using the Building Reshape Tool.. 199 Removing Area from Buildings Using the Reshape Tool ........... 200 Closing Holes in a Building Using the Building Reshape Tool ... 201 Creating a New Building Polygon Using the Reshape Tool ....... 202 Removing Building Area Using the Courtyard Cleanup Tool ...... 203 Reorienting a Building Using the Building Reorient Tool ............ 204 Regrowing Buildings Using the Building Reorient Tool .............. 205

Splitting Buildings Using the Building Reshape Tool

Before using the Building Edit Tools, you must set the options for each tool. The Building Edit tools can be used alone, or in conjunction with the SHIFT, CTRL, and ALT keys for additional shaping options.


To split buildings using the building reshape tool:

1. If you are not already in edit mode, select Editor > Start Editing on ArcMap Editor toolbar.

2. Choose the Building Reshape Tool on the LIDAR Analyst Building Edit (on page 20) toolbar.

3. Hold down the ALT key and draw a line through a building polygon. The line must begin and end outside the polygon.

198 | Building Auto-Split Tools

Appendix E

4. Double-click to end the line. Make sure you continue to hold down the ALT key until you have

double-clicked the mouse button. When you release the mouse button the system splits the building into two polygons where the line was drawn.

Figure 133: Splitting Buildings using Reshape Tool

The same image before (A) and after (B) splitting buildings where lines are drawn.



Adding to/Merging Buildings Using the Building Reshape Tool

Adding to/Merging Buildings Using the Building Reshape Tool


To add to/merge buildings using the building reshape tool:

1. If you are not already in edit mode, choose Editor > Start Editing on the ArcMap Editor (on page 24) toolbar.

2. Choose the Building Reshape Tool on the LIDAR Analyst Building Edit (on page 20) toolbar. The Building Tool Settings (on page 113) dialog displays.

3. Specify preferred parameters.

4. To merge buildings, draw a polygon around the area between the existing polygons you want to join. Be sure to overlap the borders of all polygons you are attempting to join. Double-click to close the polygon.

Note: You can either draw a box to create a square or rectangular polygon or you can draw a series of lines. When you close the polygon with a double-click, you will have a new polygon shaped where you drew the lines.

5. To add area to a building, draw a polygon beginning inside the border of the polygon to which you want to add area. Draw the shape you want and double-click to close. The system adds area to a polygon and/or merges existing polygon.

Figure 134: Adding/Merging Buildings Example

The same image before (A) and after (B) adding new area to the buildings



Appendix E

Removing Area from Buildings Using the Building Reshape Tool

You must set tool parameters before making edits.

To remove area from buildings using the building reshape tool:

1. If you are not already in edit mode, choose Editor > Start Editing on ArcMap Editor (on page 24) toolbar.


3. Hold down the SHIFT key and draw a polygon over the area you want to cut out of the existing building polygon. Double-click to close the polygon. The system redraws the existing polygon with the cut-out area excluded.

Figure 135: Removing Areas Example

The same image before (A) and after (B) removing an area from the buildings.



Closing Holes in a Building Using the Building Reshape Tool

Closing Holes in a Building Using the Building Reshape Tool

You must set tool parameters before making edits.

To close holes in a building using the building reshape tool:

1. If you are not already in edit mode, Editor > Start Editing on the ArcMap Editor (on page 24) toolbar.

2. Click the Building Reshape Tool on the LIDAR Analyst Edit Building (on page 20) toolbar. The Building Tool Setting (on page 113) dialog displays.

3. Set preferred parameters and close the dialog when complete.

4. Hold down the CTRL key and click inside the polygon from which you want to remove holes. When you release the mouse button the system removes the holes from the selected polygon. When you are done editing buildings, save your edits.

Figure 136: Closing Holes Example

The same image before (A) and after (B) removing holes from an area.


Appendix E

Creating a New Building Polygon Using the Building Reshape Tool

You must set parameters before making edits.

To create a new building polygon using the building reshape tool:

1. If you are not already in edit mode, select Editor > Start Editing on the ArcMap Editor toolbar.


3. Hold down the CTRL key and click in the center of the building you want to extract. When you release the mouse button the system automatically generates a new building polygon, as specified.

Figure 137: Create a New Building Polygon Example

The same image before (A) and after (B) creating a new building polygon.



Removing Building Area Using the Courtyard Cleanup Tool

Removing Building Area Using the Courtyard Cleanup Tool


To remove building area using the courtyard cleanup tool:

1. If you are not already in edit mode, select the Editor > Start Editing on the ArcMap Editor (on page 24) toolbar.

2. Choose the Courtyard Cleanup Tool on the LIDAR Analyst Building Edit (on page 20) toolbar.

3. Draw a box over the building(s) you want to clean up or click in a building polygon. When you release the mouse button the system automatically edits the selected polygon(s).

The system identifies multiple courtyards in the building, based on parameters specified.

Note: If your courtyards are not removed, lower the Height Sensitivity value to 50 in the

Building Tool Settings dialog box.

Figure 138: Removing Building Area Example

The same image before (A) and after (B) removing courtyard areas from the building polygon.



Appendix E

Reorienting a Building Using the Building Reorient Tool


To reorient a building using the building reorient tool:

1. If you are not already in edit mode, choose the Editor > Start Editing on the ArcMap Editor (on page 24) toolbar.

2. Click the Building Reorient Tool on the LIDAR Analyst Building Edit (on page 20) toolbar. The Building Tool Settings (on page 113) dialog displays.

3. Verify that your bare earth layer displays in the Bare Earth field. If necessary, select the correct bare earth layer.


5. Click Show Settings. The dialog expands to show the tabs.

6. Click the Building Reshape and Reorient Tools (on page 115) tab. The tab displays.

7. Click the Reset To Defaults.

8. Check the boxes next to Automatically square up buildings and Grow region using existing building extent

9. Zoom in to a building or group of buildings that are to be reoriented.

Figure 139: Buildings to be Reoriented

10. Click the Building Reorient Tool on the LIDAR Analyst Building Edit (on page 20) toolbar.

11. Hold down the CTRL key and click and drag to select a building example and set the orientation to the preferred angle.


Regrowing Buildings Using the Building Reorient Tool

12. Hold down the SHIFT key and select all buildings to be reoriented.

Figure 140: Setting Orientation to New Angle

13. Double-click anywhere in the non-building areas to initiate the reorientation process. All the selected buildings automatically become reoriented to the new set orientation.

Figure 141: Building Reorientation Results

14. Review your results and repeat the above steps for reorienting additional buildings, if necessary.

Regrowing Buildings Using the Building Reorient Tool


To regrow buildings using the building reorient tool:

1. If you are not already in edit mode, select the Editor > Start Editing on the ArcMap Editor toolbar.

2. Choose the Building Reorient Tool on the LIDAR Analyst Building Edit (on page 20) toolbar. The Building Tool Settings (on page 113) dialog displays.

3. Verify that your bare earth layer displays in the Bare Earth field. If necessary, select the correct bare earth layer.


5. Click Show Settings. The Building Tool Setting dialog expands.

6. Select the Building Reshape and Reorient Tools (on page 115) tab.

7. Click Reset To Defaults.


Appendix E

8. Check the boxes next to Automatically square up buildings and Grow region using

existing building extent.

9. Zoom in to a building or group of buildings that are to be regrown.

Figure 142: Bare Earth Layer

10. Hold down the SHIFT key then pull and drag a box around those buildings which are to be regrown.

Figure 143: Building to be Regrown

11. Hold down the ALT key and then double-click in a non-building area to activate the process. Your results should look similar to the example below.

Figure 144: Regrow Buildings Results


Index A

About LIDAR Analyst • 155 Activate Lesson 2 • 68 Activating a Data Frame • 14 Activating the LIDAR Analyst Extension • 8 Add Points to Bare Earth Tool • 159 Adding to/Merging Buildings Using the

Building Reshape Tool • 199 Adding Tools to a Toolbar • 9, 20, 163 Advanced Lesson • 65, 66 Align Elevation Data • 144 Analysis Menu • 150 Apply Coordinate System • 141 ArcMap Editor Toolbar • 23, 24, 84, 100, 180,

199, 200, 201, 203, 204 ArcMap Layer Properties Dialog - Symbology

Tab • 16 ArcMap Tools Toolbar • 83, 100 ArcMap Zoom Tools • 83, 91, 101 Attribute Buildings • 149 Attribute Trees and Forests • 149

B

Bare Earth Extraction • 33 Bare Earth Extraction (Expanded Method 1)

Dialog • 35, 51, 76, 104 Bare Earth Extraction (Expanded Method 2)

Dialog • 107 Bare Earth Extraction Dialog • 34, 35, 48, 76,

101 Bare Earth Modification Layer • 80 Bare Earth Modification Manual Edits • 83 Bare Earth Modification Settings Dialog • 55,

84, 109 Basic Setup and Preparation • 26 Basic Workflow • 26 Batch Processing • 143 Before Installing LIDAR Analyst • 6 Beginner Lesson • 25 Beginning Lesson • 25 Building Auto-Split Tool • 161, 180 Building Auto-Split Tool Tab - Building Tool

Settings • 91, 114, 181, 186 Building Auto-Split Tools • 197

Building Edit Tool Options • 161, 179 Building Edit Tools • 179 Building Extraction • 39 Building Extraction Dialog • 39, 40, 57, 88,

111 Building Reorient Tool • 161, 180 Building Reshape and Reorient Tools Tab -

Building Tool Settings • 115, 181, 187, 204, 205

Building Reshape Tool • 161, 180 Building Reshape Tool Alone • 196 Building Reshape Tool with the ALT Key •

195 Building Reshape Tool with the CTRL Key •

194 Building Reshape Tool with the SHIFT Key •

192 Building Reshape Tools • 191 Building Tool Settings Dialog • 89, 113, 181,

185, 199, 200, 201, 202, 204, 205

C

Changing Layer Symbology • 15 Classify Point Cloud • 143 Clean-up Menu • 146 Closing Holes in a Building Using the

Building Reshape Tool • 201 Closing Holes in Polygons • 194 Commands Tab - Customize Dialog • 20,

163, 168 Control Point Analyzer • 158 Convert Point Shapefile to Point Cloud • 141 Courtyard Cleanup Tool • 161, 180 Courtyard Cleanup Tool Tab - Building Tool

Settings • 116, 182, 189 Create a Project Results Folder • 27 Create Aspect Image • 150 Create Bare Earth Modification Layer • 147 Create Bare Earth Modification Layer Dialog

• 80, 118 Create Data Tile Tool • 145 Create Hill-Shade Image • 151, 157 Create LIDAR Modification Layer • 146 Create Slope Image • 150 Creating a Hillshaded DEM • 31 Creating a New Building Polygon Using the

Building Reshape Tool • 202 Creating New Polygons • 194 Crop Point Cloud • 141 Crop Raster • 158

208 | Index

Customize Dialog • 22, 165, 166 Customizing a Toolbar • 20, 162 Cutting a Polygon into Multiple Polygons •

193 Cutting Holes in Polygons • 193

D

Delete Points from Bare Earth Tool • 159 Displaying the LIDAR Analyst Toolbars • 7, 8,

9 Distributed Batch • 144 Distributed Batch Processing • 145 Distributed Dashboard • 145

E

Edit Building • 89 Edit Mode in ArcMap • 23 Ellipsoid/Geoid Height Conversion • 152 Enhance Buildings • 148 Enhancement Menu • 148 Erode/Dilate Image Tool • 162 Examining Bare Earth Results • 38 Example LAS File Information • 72 Expanding and Collapsing Layers • 14 Export to Google Earth (KML) • 151, 158 Extending Polygon Feature • 196 Extract Bare Earth/Bare Earth Extraction •

142, 157 Extract Buildings • 142, 157 Extract Contour Lines • 143 Extract Trees • 143, 157 Extraction Menu • 142

F

Feature Analyst for ArcGIS Prerequisites • 6 Feature Modeler • 152, 158 Feature Modeler Library Administrator • 153 Feature Modeler Library Browser • 153 Feature Modeler Menu • 152 First and Last Return • 3 First and/or Last Return Points • 175 Forest Extraction • 44

G

Generate NDSM • 151 Generating a Hillshade Layer • 36, 37 Getting Started • 11

H

Help Menu • 155 Hierarchical Interpolate Dialog • 77, 120 Hill-Shade and Relief Dialog • 31, 36, 37, 60,

74, 78, 87, 121

I

Import Bare Earth • 144 Installation and Activation • 5 Installing and Activating Overview • 7 Installing LIDAR Analyst • 7 Installing LIDAR Analyst 3D Viewer • 9 Introduction • 1

L

LAS Classification Statistics • 173 LAS File Information • 171, 172 LAS File Selector - Expanded View • 69, 70,

122, 123, 128, 173 LAS File Selector Dialog • 69, 70, 122 LAS Point Statistics • 177 Lesson 1

Basic LIDAR Extraction • 29

Lesson 2 Point Cloud Extraction • 67

License Manager • 153, 159 Licensing Menu • 153 LIDAR

A Brief Overview • 2

LIDAR Analyst Bare Earth Toolbar • 19, 23, 81, 84, 91, 159

LIDAR Analyst Basics • 4 LIDAR Analyst Building Edit Toolbar • 20, 89,

93, 160, 179, 181, 183, 197, 199, 200, 201, 202, 203, 204, 205

LIDAR Analyst Menus • 139 LIDAR Analyst Toolbar • 10, 19, 20, 28, 30,

31, 33, 39, 42, 44, 69, 80, 86, 88, 93, 94, 96, 156, 163, 172

LIDAR Analyst Toolbars • 19, 137 LIDAR Analyst Tools • 137 LIDAR Analyst Tools and the ArcMap

Interface • 12 LIDAR Data • 2

M

Manually Starting Edit Mode • 23 Masking Tab - Bare Earth Extraction Dialog •

54, 108


Merge Result Tiles • 145 Merging Polygon Feature • 196

N

Naming Results • 27

O

Open 3D View • 158 Opening the 3D Viewer • 10 Opening the Tutorial Project • 28, 30 Opening Your Saved Tutorial Project • 28 Optional LIDAR Analyst 3D Viewer • 9 Options Tab - Customize • 169 Output Resolution • 176 Overwatch Progress Window • 61, 124

P

Place Buildings on Bare Earth • 147 Point Cloud Bare Earth Extraction • 75 Point Cloud Building Extractions • 88 Point Cloud Classification • 96 Point Cloud File Classifier Dialog • 96, 125 Point Cloud to Multiple Rasters • 140 Point Cloud to Raster Dialog • 69, 71, 73, 127 Point Cloud to Raster with Filtering • 140,

156 Point Cloud Tools Menu • 140 Point Cloud Tree Extraction • 94 Point Cloud/LAS File Information • 171 Point Clouds • 3 Preferences • 154 Prerequisites and Installation • 6 Process Bare Earth Modifications • 147 Process Bare Earth Modifications Dialog •

86, 129 Process LIDAR Modifications • 146 Processing Bare Earth Modifications • 86 Project Tools • 143

R

Raise/Lower DEM Height Tool • 160 Raster to Vector • 162 Reassign DEM Height Tool • 160 Reference

Lesson 1 • 47

Lesson 2 • 99

Reference - Building Edit Tools • 185 Reference Manual • 155 Regrowing Buildings Using the Building

Reorient Tool • 205

Reinterpolate Hydrology • 148, 159 Remove Cars, Shrubs Tool • 160 Removing a Tool from a Toolbar • 22, 165 Removing Area from Buildings Using the

Building Reshape Tool • 200 Removing Building Area Using the Courtyard

Cleanup Tool • 203 Reorienting a Building Using the Building

Reorient Tool • 204 Repair Bare Earth • 144 Replace DEM Region Tool • 160 Reprojection • 151 Resetting a Toolbar • 22, 165 Reviewing Building Modifications • 94 Reviewing LAS File Header and Statistics •

171 Reviewing LAS File Information • 69, 70 Running a File Conversion • 73

S

Saving Edits and Stopping the Editing Process • 23

Saving Your Tutorial Project • 28 Selecting the LAS (Point Cloud) File • 68 Set Coordinate System • 141 Setting the Building Auto-Split Tool

Parameters • 181 Setting the Building Reshape and Reorient

Tool Parameters • 181 Setting the Courtyard Cleanup Tool

Parameters • 182 Setting Tool Parameters • 180 Setting Tool Parameters for Courtyard

Cleanup • 89 Settings Menu • 154 Showing and Hiding Layers • 14 Smooth Area Tool • 160 Spikes and Pits Removal • 147 Splitting Buildings Using the Building

Reshape Tool • 197 Splitting Polygon Features • 195 Square up Buildings • 149 Square up Buildings Dialog • 93, 132 Square Up Buildings Tool • 161 Square-Up Tab (Formerly) Dialog - Building

Extraction Dialog • 39, 59 Squaring up Buildings • 93

210 | Index

T

Table of Contents (ArcMap) • 13, 14, 23, 33, 41, 68, 83, 89, 93

Terrain Analysis • 151, 157 Text to Point Cloud • 141 Toolbars Tab - Customize Dialog • 167 Tree Extraction • 42 Tree Extraction Dialog • 42, 43, 44, 62, 94,

134 Trimming Polygon Features • 192 Tutorial • 155 Tutorial Document • 156 Tutorial Project • 156

U

Unprojected layer • 152 Using Building Edit Tools • 179 Using Courtyard Cleanup • 90 Using the Building Auto-Split Tool • 91, 183

V

Vector to Raster Tool • 162 View LAS Header • 140 Viewing Building Attributes • 94 Viewing the Attribute Table • 41

W

Working with Layers in the Table of Contents • 14

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LIDAR Analyst 5.1 Tutorial

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