Geographic Information

Systems

ASM215

April 2010

Larry Theller

Schedule

• Wednesday– GIS lecture– Demo of homework

• Lab – April 22

• Meet in ABE room 106a (past vending machines on left)

GIS Lecture today

• History

• Software details

• Current GIS uses

• Hot GIS trends

• Tomorrows lab

GIS Evolution

• Map viewing < Map Analysis

• Past: map layers = little files

• Now: map layers = huge databases

• Terabytes of images

• Streaming GIS data = music on the web

• Web-based tools not installed on your computer

Geographic Information Systems• “Mapping” is inventory and presentation of

spatial data.

• GIS means “Geographical Information System” – its called that because there is information

behind the map.– You “ask questions” of the data or the map

GIS is not GPS

GPS or Global Positioning Satellites – are a cloud of satellites that tell tracking devices where they are. These locations are often used in a GIS.

Trimble and ESRI

GIS vs CAD

• Difference between CAD and GIS: – you ask questions in GIS

• Three levels of GIS applications:– Inventory (What is there?)– Analysis (Answering questions)– Modeling (Making predictions)

CAD stands for Computer-Aided Design

Image: ESRI course Learning ArcGIS Desktop 2007

A GIS is a software system that connects map layers with tables of information.

Tabular Data

GIS and the internet

• GIS Users quickly adopted the internet for download of large files

• With satellite-sensors and digital camera the files soon became gigantic

• Not efficient to copy to every PC in Indiana

A GIS originally was software installed on a computer and using local files as layers with attached tables of information.

The map layer shows one building “selected” and the table has one row with information about that item.

This map is drawing data from two streaming data sources on the web and from files on the hard drive.

These high-resolution aerial photos use 8 terabytes of storage at IU, which is why you do not want to download files anymore

Named streets and property parcel lines from the Tippecanoe County GIS server

Your first GIS project outside this class will probably include anonymous layers and undocumented text files.You will need some program to look at and perhaps label these data.

Don’t Download that image

• If you don’t need to change it, maybe you don’t need to download it

• If you need to change it, edit it or clip out parts, you need to have your own copy.

• Aerial Photos – Indiana 2005 photos are:– 8500 gigabyes– Or 2000 DVD’s – Sure you want to download that?

Streaming High-resolution images

GIS software on your desktop

• ESRI ArcGIS (ArcMap, ArcCatalog)

• Other Commercial : ThinkMap, Autodesk, MapInfo

• Commercial but free Viewers:– Google Earth– ArcGIS Explorer

• Open Source GIS:– uDIG (user-friendly Desktop Internet GIS)

ESRI ArcGIS

uDIG Open Source GIS

uDIG – free and web-oriented

Scale Bar

Legend

Labels

Streaming data; databases, tables, shapefiles

The GIS program is the viewer and editor, and relies upon the database to be the complicated toolbox

uDIG – free and web-oriented

Data = streaming, database, shapefiles

PostGIS is database GIS tool

Commercial GIS viewers

• Google Earth

• ArcGIS Explorer– Collect specific streams of data from the

company– Can be expanded to use other data

Online Models

• Data comes from databases and map layers on the server

• Inputs are simplified for user

• Results may be map-based or downloaded table and reports

• Models flow data into next step

L-THIA Watershed delineation and analysis model, displays over Google Maps ™ with streaming data sets.

Location Business Services

• Target marketing geographically–Cell phone yellow pages

• Google and Mapquest, –Spots on the map

• eBay–Nearby items

Location Business Services: The geo fence

• You know when a vehicle passes into or out of a zone.

• Monitor deliveries, service staff, employees, felons, ambulances, pizza delivery guy..– http://gis2.esri.com/showcase/

showcase.cfm– http://tuxedo.esri.com/geofence/

Personal Location Services

Download topomaps and landmarks to a handheld GPS

For others, jog across the web…

A runner logs 10 miles in Central Park, and uploads his path for others.

from /run

Location Services:

• Parents use GPS to track their kids PHONES:

• "Disney Mobile will roll out a family plan of cell phones that offer features fashioned for the 11- to 15-year-old set, coupled with a generous helping of parental controls…

• Family Locator -- a tool that pinpoints the phone's position using GPS ... allows a parent to get the location of his or her child's handset by entering a self-selected PIN into a Web site or a phone. "

http://www.mobile-tech-today.com/news/Meet-the-Cell-Phone-Tracking-Parents/story.xhtml?story_id=011000DGX45F

Location Services:

• Parents use GPS to track their kids cars:http://www.npr.org/templates/story/story.php?storyId=5725196

– "For example, says Alltrack's Mark Allbaugh, when a teen driver is speeding, parents can remotely flash the car's light or honk the horn, until the teen slows down. "

The Lab Exercise

• Indiana Sex Offenders Registry

• Indiana Map – an online map

• Google Earth, around the world.

Drop-down Menus

ActiveLayer

Identify

Layer Menus

Zoom in to Brazil, Indiana and answer questions.

Click the identify button, then the map, for data about the “Active Layer.” A floating pop-up appears with the data.

THE END

• See you tomorrow

• Room 106A in ABE building.

Introduction to GIS Analysis

GIS or Spatial analysis: application of operations or functions to spatial data to add value, support decisions, and reveal patterns.

• Geoprocessing (according to ESRI): GIS operation in which new data is derived from existing data.

http://news.uk.msn.com/monks-protest-in-burma.aspx

The GIS analytical process

Explained in Module 6, ESRI online course

1. Define the problem 2. Define the criteria 3. Identify the data you

need 4. Plan the analysis 5. Prepare the data for

analysis 6. Execute the analysis 7. Examine and present the

results

Example: Map of cholera outbreak, 1854

• (Based on John Snow’s map)

• Other analysis examples?

Spatial Analysis is considered the crux of GIS. Why?• Spatial analysis is the means of adding

value to geographic data.

• It turns data into information

• Spatial analysis can reveal things that might otherwise be invisible. It can make what is implicit explicit.

More about spatial analysis…

• Some methods are highly mathematical.

• All effective spatial analysis requires an intelligent user, not just a powerful computer.

• “Spatial analysis is best seen as a collaboration between the computer and the human, in which both play vital roles.” (Geographic Information Systems and Science, Wiley, 2001)

Overlay

• Combine spatial and attribute data from two or more spatial data layers

• Union and Intersect most common

Buffers

• Buffer = region that is less than or equal to a specified distance from a feature or features

• Can buffer point, line or area feature• Raster or vector data

Vector buffers

• May be applied to points, lines, or areas, but always produces an area

• For point data, creates circles around each point feature

Buffering on vector line data

• Circles are created centered at each node or vertex

• Tangent lines are generated parallel to feature input lines

• Tangent lines and circles are dissolved together

Clip, Intersect, and Union