Hello I am trying to calculate the standard deviation of a stack of 45 raster image files. I initally tried writing a simple script using Arcpy, but the results were not what I expected (values were very large and non-sensical). My script was identical to ones I used for calculating the sum and mean of the same rasters. The scripts worked perfectly. But when I replaced "sum" or "mean" with "STD", there was a problem.