Map Algebra and Python?

Discussion created by bhutaaa on Sep 2, 2011
Latest reply on Sep 27, 2011 by bhutaaa
Hey all,

I'm trying to input two rasters and derive a "mean" raster from both of them.  The thing is I need to do this 4500 times.  Any help would be appreciated.  I've been messing around with a code, but I don't even know if I have it right.  Right now, it runs successfully but no output and I'm thinking this is because I forgot to define something?

Also, I don't know even if I can run it like the way I envision it? 
What I'm trying to do is
mean (1895_01Tmin, 1895_02Tmax) = 1895_01Tmean
mean (1895_02Timin, 1895_02tmax) = 1895_02Tmean
mean (XXX_XXTmin, XXXX_XXTmax) = XXXX_XXTmean

I posted my code below and I really appreciate any help!

# Import system modules
import sys, string, os, arcgisscripting

# Create the Geoprocessor object
gp = arcgisscripting.create()
gp.OverWriteOutput = 1

# Parameters
Workspace01 = gp.GetParameterAsText(0)
gp.AddMessage ("input Workspace01: " + Workspace01)
#Workspace01 = "C:\test\ppt_study_counties"

Workspace02 = gp.GetParameterAsText(1)
gp.AddMessage ("input Workspace02: " + Workspace02)
#Workspace02 = "C:\test\ppt_study_counties"

output_Workspace = gp.GetParameterAsText(2)
gp.AddMessage ("output Workspace: " + output_Workspace)
#OutWorkspace01 = "C:\test\zonal_stats_ppt_counties"

    #Get the raster datasets in the input Workspace01 and loop through them from the start
    gp.Workspace01 = Workspace01
    InputRasters01 = gp.ListRasters01()
    InputRaster01 =

    gp.Workspace02 = Workspace02
    InputRasters02 = gp.ListRasters02()
    InputRaster02 =

    while InputRaster:

        #Set the output table name
        outRaster = OutputWorkspace + "\\" + Workspace01 + Workspace02 + "tmen"
        InExpression = "MEAN(Workspace01, Workspace02)"

        # Check out Spatial Analyst extension license

        # Load required toolboxes.  You may need to alter the paths if you are using a 64 bit OS
        #gp.AddToolbox("C:\Program Files (x86)\ArcGIS\ArcToolbox\Toolboxes\Spatial Analyst Tools.tbx")

        # Process: MapAlgebra
        gp.SingleOutputMapAlgebra_sa(InExpression, Outfile)
        # print InputRaster
        InputRaster =

    print gp.GetMessages(2)