topic CELL STATISTICS with LIST RASTERS in Python Questions

CELL STATISTICS with LIST RASTERS

anTonialcaraz — Sat, 11 Dec 2021 22:27:52 GMT

Hi,

I'm trying to run Mean annual cell statistics for groups of monthly rasters.

The output I'm getting is the same as the last raster in the list ("camp_t_srf_sep" in this example) so i assume the script is not actually iterating through all rasters.

Any help will be greatly appreciate it.

# Example of list of rasters:
 # camp_t_srf_apr
 # camp_t_srf_aug
 # camp_t_srf_dec
 # camp_t_srf_feb
 # camp_t_srf_jan
 # camp_t_srf_jul
 # camp_t_srf_jun
 # camp_t_srf_mar
 # camp_t_srf_may
 # camp_t_srf_nov
 # camp_t_srf_oct
 # camp_t_srf_sep

import arcpy
from arcpy import env
from arcpy.sa import *
arcpy.CheckOutExtension("Spatial")
env.overwriteOutput = True
env.extent = arcpy.Extent(-180.0, -90.0, 180.0, 90.0)

env.workspace = arcpy.GetParameterAsText(0)
StageAge = arcpy.GetParameterAsText(1)


rasterlist = arcpy.ListRasters(StageAge + "_*")
for raster in rasterlist:
    output_mean = CellStatistics(raster, "MEAN", "DATA")
    output_mean.save(env.workspace + "\\" + raster[:11] + "ann")‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: CELL STATISTICS with LIST RASTERS

anTonialcaraz — Mon, 23 Apr 2018 12:02:50 GMT

just to add that I'm using 10.2.1 at the moment.

many thanks

Re: CELL STATISTICS with LIST RASTERS

DanPatterson_Retired — Mon, 23 Apr 2018 12:05:45 GMT

Throw a print statement in... just to make sure you are getting the correct names, it will silently do nothing otherwise

And also.. Cell statistics expects a list/stack of rasters, not one at a time

http://desktop.arcgis.com/en/arcmap/latest/tools/spatial-analyst-toolbox/cell-statistics.htm

Re: CELL STATISTICS with LIST RASTERS

anTonialcaraz — Mon, 23 Apr 2018 12:35:04 GMT

Thank you Dan.

yes, the print statement gives me the list of rasters I want to calculate the mean from.

I thought I was giving the script the list of rasters with the variable rasterlist. I don't quite understand why it only processes the last raster in the list.

Re: CELL STATISTICS with LIST RASTERS

DanPatterson_Retired — Mon, 23 Apr 2018 12:36:48 GMT

because you are cycling through each raster one at a time.

for raster in rasterlist:

give it the whole list... examine the syntax in the code sample in the link I provided

Re: CELL STATISTICS with LIST RASTERS

anTonialcaraz — Sat, 11 Dec 2021 22:27:55 GMT

I know it works like as below. Just thought there would be a more elegant and economic way to put it using ListRasters

rasterlist5 = [StageAge + "_t_srf_apr", StageAge + "_t_srf_aug", StageAge + "_t_srf_dec", StageAge + "_t_srf_feb", StageAge + "_t_srf_jan", StageAge + "_t_srf_jul", StageAge + "_t_srf_jun", \
 StageAge + "_t_srf_mar", StageAge + "_t_srf_may", StageAge + "_t_srf_nov", StageAge + "_t_srf_oct", StageAge + "_t_srf_sep"]

output_mean = CellStatistics(rasterlist5, "MEAN", "DATA")

output_mean.save(OUTWorkspace + "\\" + raster[:11] + "ann")‍‍‍‍‍‍‍‍‍‍

Re: CELL STATISTICS with LIST RASTERS

DanPatterson_Retired — Mon, 23 Apr 2018 12:51:28 GMT

You can use your for loop to build the list... just don't have cellstatistics in the loop

Re: CELL STATISTICS with LIST RASTERS

anTonialcaraz — Sat, 11 Dec 2021 22:27:58 GMT

I see what you mean. Thanks so much Dan.

rasterlist5 = arcpy.ListRasters(StageAge + "_*")

for raster in rasterlist5:
    print raster

output_mean = CellStatistics(rasterlist5, "MEAN", "DATA")
output_mean.save(env.workspace + "\\" + raster[:11] + "ann")‍‍‍‍‍‍‍‍‍‍‍‍