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 -6. This seems like a strange value ramp, is it correct?
One possibility is that one of the supervised images is showing it's values as 4 and 7 and not 1 and 2 (which is what the other image has). I've opened the raster attribute table for the 4 and 7 value image, and created a new column, populating it with values 1 and 2. It seems I can't use "Delete Field" to delete the original value field, but I exported it as a new raster and was able to use "Delete Field" to delete the 4 and 7 value field, however this seems to have created an internal problem as the symbology is stuck on the original Value field of 4 and 71.
If the 1 to -6 value ramp My question is correct, how to interpret it? 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