I'm currently analyzing the change detection for urban expansion over a decade starting from 2006-2016. How can I use raster calculator in order to know the changes? For example, from agriculture to urban area and etc. I already classified the images into 4 classes, urban area,vegetation,water bodies and barren land.
Try reclassifying the rasters to a different scale of numbers, such as
urban = 1 ag = 10 forest = 100 water = 1000
Then just subtract the rasters in Raster Calculator:
0 will mean unchanged. 9 will mean ag --> urban -9 will mean urban --> ag 99 will mean forest --> urban 90 will mean forest --> ag -99 will mean urban --> forest etc.