Hi thereI've encountered some odd behaviour with the Con tool that I can't seem to work o.I have one input landcover classification raster. I then want to combine two classes within it, that is then divided by whether or not they lie within a road buffer.So, using an arcpy script:- I create a mask from the original raster that simply contains 1 values for the original combined classes- use Extract by Mask to create a second mask that only contains 1's where the combined classes are overlapped by road buffer polygons- reinsert that into the original raster with a new value (let's say 15) using the Con tool.However, when I do this final step I end up with an output raster that only contains these 15 pixels and NoData everywhere else. eg:# inputs in_ras = r"C:\test\landcover.gdb\lcc" # input landcover classification raster road_buffer = r"C:\test\landcover.gdb\buffer700" # road buffer polygon layer arcpy.Raster(in_ras) # combine two classes from input raster into a mask combined = arcpy.sa.Con((in_ras == 2) | (in_ras == 13), 1) # extract pixels in the combined mask that lie within the road_buffer into a new mask combined_road_buff = arcpy.sa.ExtractByMask(combined, road_buffer) # create output raster with the new class as 15, and the original raster everywhere else out_ras = arcpy.sa.Con(combined_road_buff == 1, 15, in_ras)
Now for whatever reason (and I've tested this manually using the raster calculator too), the final output raster is basically a mask of the new class with NoData everywhere else (ie identical to combined_road_buff). I tested using a constant value as the false condition instead of a raster and I get the same result. Yet changing the final Con operation to:out_ras = arcpy.sa.Con(arcpy.sa.IsNull(combined_road_buff), in_ras, 15)
gives the desired result, with the new class combined with the original classification.Can anyone advise on what is going on here?(and if anyone has a more efficient way to do what I'm doing, feel free to point it out!)CheersMalcolm
