I've run OD cost matrix analysis using GUI tools n ArcGIS 10.
My goal is relatively simple - find closest 50 neighbors for each origin point.
The dataset I'm working with is relatively large:
- network dataset consists of ~ 1.16 million elements
- there are ~ 100k origins
- and ~ 1.3 million destinations.
Origins are part of the destinations dataset.
The limits I set for the geoprocessing tool are: default_number_destinations_to_find set to 51 (since first 'neighbor' will be the same, overlapping point) and default_cutoff = 50000 (since I know from previous analyses that this value cannot be larger than that).
In order to save memory (I think) I go with output_path_shape set to NO_LINES - I do not need graphical representation of OD matrix - just tabular data (correct me if I'm wrong here).
It takes a while to process this task (~ 24h), but nonetheless I get the results. So far so good.
In order to automate this task I tried putting all this steps into python script and came up with:
try:
import arcpy
from arcpy import env
# Check out any necessary licenses
arcpy.CheckOutExtension("Network")
# set environment settings
env.workspace = "D:\\GIS\\04-buildings.gdb"
env.overwriteOutput = True
# Local variables:
NW_FIX_ND = "D:\\GIS\\02-network-restrict.gdb\\NW_FIX\\NW_FIX_ND"
DESTINATIONS = "buildings\\destinations"
ORIGINS = "buildings\\origins_1"
OD_COST_MATRIX = "OD Cost Matrix"
LINES = "OD Cost Matrix\\Lines"
bn_1 = "results\\bn_1"
# Make OD Cost Matrix Layer
arcpy.MakeODCostMatrixLayer_na(NW_FIX_ND, "OD Cost Matrix", "Length", "50000", "51", "Length", "ALLOW_UTURNS", "restriction", "NO_HIERARCHY", "", "NO_LINES")
# Add Destinations
arcpy.AddLocations_na(OD_COST_MATRIX, "Destinations", DESTINATIONS, "Name h_gebaeude_id #;CurbApproach # 0", "5000 Meters", "", "TLM_STRASSE_RESTR_FIX SHAPE;NW_FIX_ND_Junctions NONE", "MATCH_TO_CLOSEST", "APPEND", "NO_SNAP", "5 Meters", "EXCLUDE", "TLM_STRASSE_RESTR_FIX #;NW_FIX_ND_Junctions #")
# Add Origins
arcpy.AddLocations_na(OD_COST_MATRIX, "Origins", ORIGINS, "Name h_gebaeude_id #;TargetDestinationCount # 51;CurbApproach # 0;Cutoff_Length # #", "5000 Meters", "", "TLM_STRASSE_RESTR_FIX SHAPE;NW_FIX_ND_Junctions NONE", "MATCH_TO_CLOSEST", "CLEAR", "NO_SNAP", "5 Meters", "EXCLUDE", "TLM_STRASSE_RESTR_FIX #;NW_FIX_ND_Junctions #")
# Solve
arcpy.Solve_na(OD_COST_MATRIX, "SKIP", "TERMINATE")
# Select OD Lines
arcpy.SelectData_management(OD_COST_MATRIX, "Lines")
# Select
arcpy.Select_analysis(LINES, bn_1, "")
print "Completed successfully"
except Exception as e:
# If an error occurred, print line number and error message
import traceback, sys
tb = sys.exc_info()[2]
print "An error occured on line %i" % tb.tb_lineno
print str(e)
However, when I attempt to run this script I get the following error:
An error occured on line 39
ERROR 030024: Solve returned a failure.
Out of memory.
Failed to execute (Solve).
Why does arcpy fail when GUI could do the job?
My reasoning was that by running the task in python, and avoiding the graphical overhead, it should even work faster.
