Failed to execute EucAllocation - arcpy

Question

Im unable to get EucAllocation function working in ArcMap 10.5.1 or via Arcpy. I've used user guides for info but with no joy - http://desktop.arcgis.com/en/arcmap/10.5/tools/spatial-analyst-toolbox/euclidean-allocation.htm. I have noticed that using the "copy code snippet" from ArcMap is different to the format in above link.

code snippet (using defaults) = arcpy.gp.EucAllocation_sa(input,output, "", "", "5", "Value", "", "")

I have added the function where problematic part of the python script is. The code is generating a floodplain dataset from a DEM raster.

def create_floodplain(root_folder, in_gdb_name, working_gdb_name):

    # use output of get_raster function as input
    raster = get_raster(root_folder, in_gdb_name)

    working_gdb = os.path.join(root_folder, working_gdb_name)

    output_root = os.path.join(working_gdb, raster)
    #1 Raster Calc - convert DEM from floating point to int
    output_p1 = os.path.join(output_root + "_p1_rastercalc_TEST")

    print "Step 1. Running Raster Calculator...."
    rast_calc = Int(str(raster))
    # save output
    rast_calc.save(output_p1)
    print "Raster Calculator complete - %s" % (os.path.basename(output_p1))

    #2 Extract by Mask - create water boundary (ridgeline) raster
    input_p2 = output_p1
    mask_fc = os.path.join(working_gdb, "WATER_POLY_Clip16")
    output_p2 = os.path.join(output_root + "_p2_extractmask_TEST")

    print "Step 2. Running Extract By Mask...."
    ext_by_mask = ExtractByMask(input_p2, mask_fc)
    # save output
    ext_by_mask.save(output_p2)
    print "Extract By Mask complete - %s" % (os.path.basename(output_p2))

    #3 Euclidean Allocation - calculates, for each cell, the elevation value of the nearest ridgeline
    input_p3 = output_p2
    mask_fc = os.path.join(working_gdb, "WATER_POLY_Clip16")
    output_p3 = os.path.join(output_root + "_p3_euclideanallocation_TEST")

    print "Step 3. Running Euclidean Allocation...."
    euc_allocate = EucAllocation(input_p3, "", "", "5", "Value", "", "")
    # save output
    eucAllocate.save(output_p3)
    print "Euclidean Allocation complete - %s" % (os.path.basename(output_p3))

    #4 Raster Calc - create vertical buffer where 3 is the required buffer height (m)
    input_p4 = output_p3
    output_p4 = os.path.join(output_root + "_p4_rastercalc_TEST")

    print "Step 4. Running Raster Calculator...."
    rast_calc = raster >= (input_p4 + 3)
    # save output
    rast_calc.save(output_p4)
    print "Raster Calculator complete - %s" % (os.path.basename(output_p4))

The running of the EucAllocation (Step 3) in the above code is causing the issue as it is resulting in the below error:

ExecuteError: ERROR 999999: Error executing function. A column was specified that does not exist. A column was specified that does not exist. The table was not found. [VAT_EucAllo_Suir1] No spatial reference exists. ERROR 010296: Error in writing raster C:\Users\XXX\AppData\Local\Temp\t_t83.tif. Distance mapping is failed. ERROR 010067: Error in executing grid expression. Failed to execute(EucAllocation).

Answer 1

After Step 2, run arcpy.BuildRasterAttributeTable_management(output_p2, 'Overwrite').

The attribute table isn't necessarily created automatically after ExtractByMask or any other process. I've never figured out the rules for when it is/isn't, but I find it good practice to go ahead and build it after many operations.

See http://desktop.arcgis.com/en/arcmap/10.5/tools/data-management-toolbox/build-raster-attribute-table.htm