How to capture Google Earth images for use in ENVI

How to capture Google Earth images for use in ENVI

There are times when you may want to capture high resolution screenshots form Google Earth to use in ENVI software.  This could be for background display, ground truthing, or viewing historical imagery.  Basically in Google Earth you will navigate to the area you wish to capture and place markers in each corner.  After saving the image you will use these corner markers to georeferenced your image in ENVI or ArcMap. 

This document is based on information in the UCLA Introduction to GIS page “How To: Add a Google Earth Satellite Image Into ArcMap” located at:
 http://gis.yohman.com/up206a/how-tos/how-to-add-a-google-earth-satellite-image-into-arcmap/

Preparing and capturing the Google image

Follow the Google Earth section on the above link for detailed instructions on placing corner markers.  We recommend using Google Earth Pro, rather than Google Earth, to capture a higher resolution image.  Google Earth Pro is installed on all of the PCs in the YCEO Lab.  You may need to enter your email address as the username and the password GEPFREE.  When you select File | Save | Save Image three buttons are placed above the image.  Click on Map Options to turn off the various map elements.  Click on the Resolution button and select Maximum.  Finally click on the Save Image button to capture the image.

The UCLA page provides instructions on how to georeference the image using ArcMap.  Below are instructions on how to georeference the captured image using ENVI.

Using ENVI

  • Open saved image in a new View in ENVI
  • From the Toolbox select Geometric Correction | Registration | Registration Image to Map
  • Select the RGB bands of image to register
  • Increase the resolution to retain more detail:    0.00003513 for example
  • Select the Upper Left center point and enter the saved Lon and Lat values
  • Click Add Point to save this
  • Repeat this step for the three remaining corners
  • From GCP Selection dialog
    • Options | Warp (Displayed bands or File)
    • Use Bi Linear interpolation
  • Open a new view and display your image

This image could be saved as a GeoPDF and used on a tablet or phone with the Avenza PDF Maps application.

Category: 
Techniques