Thanks Ryan for posting the python code, I was able to modify and use it to add hundreds of rasters together. The following is the modified code for my purposes, hopefully it endevours to help someone else out in the future. import arcpy import os arcpy.CheckOutExtension('Spatial') arcpy.env.scratchWorkspace = "datapath" arcpy.env.workspace = "datapath" #create a list of rasters in the workspace rasters = arcpy.ListRasters("*", "GRID") i = 0 #loop through rasters in list for raster in rasters: print "processing raster: %s" %os.path.join("datapath",raster) #get first raster out1 = raster #sum rasters together if i == 0: out2 = arcpy.Raster(out1) i += 1 else: out2 = out2 + out1 i += 1 #save final output out2.save(os.path.join("outpath",'sumRas')) - Micheline
... View more