Image Difference Analysis: help interpreting results

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11-18-2013 06:20 AM
DavidMeek
New Contributor II
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I'm working for the first time with ArcMap's relatively new image analysis window, and am using the "image difference" function to calculate change between two images which I have performed a supervised classification on.

Each of the two images have only two types of land cover, forest and pasture; however, when I conduct the "image difference" analysis, I receive a raster with a ramp of 1 to -1. My question is how to interpret it? Swiping between the two images provides some clues as to what the ramp should mean, i.e. a large area that is forested in image 1 is deforested in image 2, but the other ramp colors are inconclusive I.e. I'm looking to be able to symbolize where forest remains forest, forest changes to pasture, pasture remains pasture, and pasture changes to forest. I know this should be easy, and is so in ERDAS, but can't figure it out in ArcMap. Thanks in advance for any suggestions, David
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