Iterate and add rasters from multiple folders

GeorgeSutherland

Hello,

I am trying to add raster files from four folders together (i.e. file1 from folder1 + file1 from folder2 +file1 from folder3 + file1 from folder4). This would be easy enough to do with the Raster Calculator tool, however there are 90 files in each folder, each needing to be combined with the corresponding files in separate folders.

Using Model Builder I have create a model that allows me to select four input files to be added together, and assigns the output raster to a new location. I can batch process this, but when I press "fill" to fill in the other 90 files for each of the four folders, the original four files just get filled in the whole way, resulting in me having to manually change each of the names.

Just wondering if there is any way to build a model or write a script that will iterate through all four folders, pull out the same file in each folder, and add them together, for example:
file1 from folder1 + file1 from folder2 +file1 from folder3 + file1 from folder4 = output1,
file2 from folder1 + file2 from folder2 +file2 from folder3 + file2 from folder4 = output 2
.....
file'n' from folder1 + file'n' from folder2 +file'n' from folder3 + file'n' from folder4 = output'n'

Thanks in advance for any help!

JakeSkinner

Hi George,

You could accomplish this in a python script.  Ex:

import arcpy from arcpy import env from arcpy.sa import * env.workspace = r"C:\folder1"  list = [] for raster in arcpy.ListRasters("*"):     list.append(raster)  for n in list:     env.workspace = r"C:\folder2"     if n in arcpy.ListRasters("*"):         ras2 = n     outPlus1 = Plus(n, ras2)     env.workspace = r"C:\folder3"     if n in arcpy.ListRasters("*"):         ras3 = n     env.workspace = r"C:\folder4"     if n in arcpy.ListRasters("*"):         ras4 = n     outPlus2 = Plus(ras3, ras4)     outPlus3 = Plus(outPlus1, outPlus2)     outPlus3.save(r"C:\output" + "\\" + n)

What the code is doing is iterating through folder1 and appending all rasters to a list.  Then the code iterates through the list and finds each raster in folder2, folder3, and folder4.  With a python script you cannot use the Raster Calculator, so you will need to use the Plus tool for spatial analyst.  Therefore, you will need to sum the rasters from folder1 and folder2, then sum the rasters folder3 and folder4, and then finally sum the outputs from these two.