Updating table fields from a raster file

Question

Hi there! I have some raster files in grid format with signed integer pixels in which I want to add some fields in their table then compute values with some formulas in the new fields. I managed to add the fields but I'm struggling with the second part. I tried with arcpy.da.UpdateCursor but it returns a RuntimeError: 'in_table' is not a table or a feature class. It seems clear for me that I can not use this function with raster file. Is there a way to compute the values directly in the raster or do I have to try a different approach? How? The code is: import arcpy as ap import os import random_function as rf # change name after from arcpy.sa import * if ap.CheckExtension('Spatial') == 'Available': ap.CheckOutExtension('Spatial') else: print('Spatial Analyst extension is not available') # Setting environments & paths ap.env.workspace = os.path.join("D:\", "master", "_thesis_data") ap.env.scratchWorkspace = os.path.join(ap.env.workspace, "temp") ap.env.overwriteOutput = True inp_ws = ap.env.workspace temp_ws = ap.env.scratchWorkspace lu_folder = os.path.join(inp_ws, "lu") lu_scenarios = [] for dirpath, dirnames, filenames in ap.da.Walk(lu_folder, datatype='RasterDataset'): for f in filenames: lu_scenarios.append(os.path.join(dirpath,f)) # Setting input data climate = Raster("climate_c") clim_soil = Raster("rc_climsoil_c") tbl_uSOCr = os.path.join(inp_ws, "uSOCr.txt") tbl_uSOCf = os.path.join(inp_ws, "uSOCf.txt") tbl_uBCi = os.path.join(inp_ws, "uBCi.txt") for (sc, lu_sc) in enumerate(lu_scenarios): lu = Raster(lu_sc) clim_lu = climate + lu soc_f1k = ReclassByTable(clim_lu, tbl_uSOCf, "id", "id", "soc_factor") soc_r1k = ReclassByTable(clim_soil, tbl_uSOCr, "id", "id", "soc_ref") soc_1k = (soc_f1k*soc_r1k)/1000 bc_1k = ReclassByTable(clim_lu, tbl_uBCi, "id", "id", "bcs") tc_1k = (soc_1k + bc_1k) tc_1k_new_fields = ["tc", "tot_ha", "tot_cs"] for field in tc_1k_new_fields: ap.AddField_management(tc_1k, field, "FLOAT", 12, 4) with ap.da.UpdateCursor(tc_1k, "*") as cursor: tc_all_fields = [f.name for f in arcpy.ListFields(tc_1k)] VALUE, COUNT, tc, tot_ha, tot_cs = row[1], row[2], row[3], row[4], row[5] for row in cursor: tc = VALUE/1000 tot_ha = COUNT*2500 tot_cs = tc*tot_ha cursor.updateRow(row) if ap.GetRasterProperties_management(tc_1k, "ALLNODATA"): tc_1k.save(temp_ws + "\" + "0sc" + str(sc) + "_tc" + str(mc_counter+1)) # ==> TESTING DATA!!! print tc_1k‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ Thanks again!

DanPatterson_Retired · Answer

I have lots of NumPy examples on my blog post if you are interested in numpy functionality with arcpy and other modules.

RenanBarroso · Answer

Thank you! Now it is working and I've changed all my raster processing to NumpyArray. Much better!

XanderBakker · Answer

The cursors in the da module do not provide access to raster attribute tables (RAT). The old cursors do. Although I have never used it to write to a RAT, I have used the old cursors to read from it...

https://community.esri.com/message/355845?commentID=355845#comment-633411