When I tried to compare two rasters in Arcgis by using Raster Calculator, the resulting raster includes positive and negative values.
How can I interpret these values?
What does the mean of the negative values?
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.Sign up to join this community
assuming that both rasters reflect the same variable on different dates and value scales, for example NDVI start date (NDVI-i) - NDVI end date (NDVI-f). Assuming you performed the operation NDVI-f - NDVI-i:
I understand that ArcGis has tools for detecting changes, so you might want to look into it.
Another aspect, instead of working with the change of signs, negative or positive. It is advisable to define a threshold of change, ie, what range you consider a significant change. For example, for a scale of 0 to 1, you could decide as threshold value 0.03, values below this range are not considered a change.