Post on 17-Aug-2014
description
transcript
Google Earth:Poor Man’s GIS, Fabulous Tool!
Where to Get Help and Info
Google Earth User Guide: http://earth.google.com/userguide/v4/
Google Earth Help Group: http://groups.google.com/group/earth-help/
Google Earth blog: http://www.gearthblog.com/
The Basics
Finding locationsUsing layersAdding locations and layersNavigatingGetting coordinates
Opening ViewSearching for locations
Search for Location
Works like in Google Maps: Named location or Address or Latitude and longitude
Zoom or “fly” to location by double-clickingSave desired locations to “My Places”
Opening View
Saved locations
Saved LocationsSame as any other file management:
Drag-and-drop Create folders to organize site information Give meaningful names
Anything under “My Places” will be savedAnything under “Temporary Places” is
gone after you shut Google Earth
Opening View
Ready-Made Layers
Ready-Made Layers
Lots of pre-compiled informationCan make it really slow to loadCan make it confusing to navigate
Unselect most or all to navigateSelect only the ones you need, once you’re
close to your location
Some Useful LayersGeographic Web:RoadsBorders and LabelsTerrain (3D effect)
EarthquakesVolcanoesParksHospitalsSchools
And as usual: Garbage in, garbage out
(i.e., the databases are not 100% accurate)
Getting More Layers National Wetlands Inventory: http://
www.fws.gov/nwi/WetlandsData/GoogleEarth.htm USGS Earthquake Hazard Program: http://
earthquake.usgs.gov/research/data/google_earth.php Humboldt Bay Trail network:
http://www.green-wheels.org/node/313 Google Earth Gallery:
http://www.google.com/ig/directory?synd=earth
Navigation - 1Mouse left-click lets you pan: drag or spin the
globe while your point-of-view remains fixedMouse right-click lets you fly: move your
point-of-view up, down, and around a fixed location target
Scroll wheel lets you zoom straight in and out vertically
Navigating - 2Sliders let you pan and fly as wellDouble-click “North” to reset orientationVertical slider tilts the point-of-viewArrows pan north, south, east, westNumbers pad: + and – let you zoom
straight in and out vertically
Getting Coordinates
For the new project initiation procedure, we’ll need project coordinates. Navigate to the project site Place your mouse cursor over the location Read the latitude and longitude off the bottom
status bar
Mouse cursor
Coordinates
Fun Stuff
Inserting placemarksInserting polygons and pathsMeasuring distances
Placing and Moving Points
Use different markersAdd labels and coloursRight-click to editPossible project uses:
Points of interest (e.g., water tank, hospital) Sampling locations
Add Placemark tool button
Marker style
Add label and description
Proposed monitoring wells
Creating Polygons and PathsPolygon: Closed shape, filled or outlined
e.g., Site boundary, building footprintPath: Curved line, open shape
e.g., Road, trail, fault line, groundwater levelsBoth can be drawn point-to-point or
freehand (create lots of points)Can edit, delete, add or move points
Measuring DistancesLine (btwn two points) or Path (multipoint)Choose units: feet, yards, miles, etc.Move the nodes to desired locationsFollows surface (“walked” distance)Check “Mouse Navigation” to move
around, then uncheck to continue measuring
The Really Cool Stuff
Importing maps, site plans, and aerial photos
Sharing files and collaboratingSaving images
Overlays 1: Inserting a MapThis is what you use when your map has
latitude and longitudeMap needs to be in a recognized format,
such as PNG, GIF, JPEG, BMP, or TIFFMap needs to be in cylindrical projection
(or small enough to be close)Memory hog: keep your images small
(<2000 x 2000 pixels)
Inserting a Map (Cont.)
Find the map then convert it to the right format
Navigate to known latitude and longitude
Importing a Map (Cont.)Show grid (under View drop-down menu)Google Earth automatically re-projects
cylindrical projectionLine up the map’s longitude and latitude
using the handlesSlide image transparency to make it easier
to align
Overlays 2: Inserting a Site Plan
More fiddly, inexact, but useful!Same file formatsMay need to capture a PDF or ACAD file
and save it to a usable formatInclude some reference points to line up
with the terrain
Site layout from ACAD file
Inserting an Air Photo
Patching up the record with better or more recent air photos
Photos need to be ortho-rectifiedWorks the same as inserting a site plan
Air photo to fill obscured area
Google Earth jazz
Adding it all together, e.g.: Draped maps over contours Site map plus sampling locations plus wetland
polygons Project footprint plus fault lines
Support project decisions
Geology draped over terrain
Wetlands and wells
Sharing Google Earth FilesKeep your files organizedSave the folder containing files to share:
Points, polygons, paths, map overlays, photosSaved as a single .KMZ file, can be kept in
the project folderSaves small, easy to e-mailOther people can edit and re-save
Saving as JPEG
Allows you to save screen content as just an image (can’t edit points in Google Earth)