A brief overview of viewing images in Imagine

 

Lab Goals

 

The goals of this lab are:

 

1)      to introduce you to some of the key commands in ERDAS Imagine for viewing raster images and extracting basic geographic information from them.

 

2)      To introduce you to the concepts of visualizing digital numbers as colors on the screen. 

 

Data

 

We will look at a Landsat image of Georgia and a soils maps from the same area.  These images are provided by ERDAS as part of their training tutorials.

 

Background Information

 

A truly excellent overview of remote sensing concepts, remote sensing data, and fundamental data processing approaches can be found via Help key in ERDAS Imagine, which among other things, directs you to the ERDAS Field Guide.   If you are more concerned with which button to push in Imagine to access the various subroutines, then visit the ERDAS Imagine Tour Guides, which has a number of tutorials for different functions in Imagine.  These two manual can also be found at:

 

C:\Program Files\IMAGINE 8.5\help\html\intro\copyrights.htm

 

C:\Program Files\IMAGINE 8.5\help\hardcopy\TourGuide.pdf

 

The lab: An outline of topics covered in the lab session

 

Most of this lab consists of a show and tell with the instructor running the commands, discussing the image and image data, and having you follow along.  Most (but not all) of the commands that we will cover today are presented in more detail in the Viewer Chapter of the ERDAS Imagine Tour Guides.  Topics we will cover are:

 

Preference Menu (under session on menu)

            Home directory

 

Opening a raster file

  • Choosing a  file: Click on icon go to File/Open/Raster Layer in menu
    • Type in file name
    • Browse
    • Click on recent files
  • Raster options
    • Assigning bands
      • True color (bands 3,2,1)
      • False color composite (other combinations)
    • Color, black & white, relief

 

Utility Menu (on View Window)

  • Cursor Inquiry (via Utility or + icon)
    • Geographic coordinate information
    • Pixel value information
    • Changing color/shape of cursor (use Utility menu)
  • Measurement Tool (via Utility menu or Ruler icon)
    •  Coordinate data
    • Polyline data
    • Polygon
    • Changing units (Edit tab on Measurement Tool window)
  • Layer Information  (via Utility Menu)
  • Mage merges
    • First open second image
    • Swipe
    • Blend
    • Flicker

 

View Menu on View Window

  • Arrange Layers
    • Make sure second image is open
    • Open arrange layers dialog
  • Zooming (via right click on window, icons, or view menu)
    • In/out icons
    • Magnifying glass icons
    • Right click in view window
    • Magnifying box (Create Magnifier in Viewer menu)
  • Display two images that are linked geographically
    • Have both images open, one on top of the other
    • Go to View/Split/Split Horizontal on the View Menu
    • Open the file name in the Select Layer to Add on the new viewer
    • Go to View/Link-Unlink Viewers/Geographical
  • Rotate/flip etc. –on the View Menu

 

Raster Menu on View Window

  • Band Combinations on Raster Menu
    • Play with variations
    • Think on what meaning of image is when all IR bands are shown

 

Profiling Tool on View Window: Think on meaning of

·        Spectral profile

·        Spatial profile

·        Surface profile