I am trying to create and update a field with a count of line features (tLayer
) within a distance of point features (sLayer
). I am attempting to use a combination of AddField_management
, arcpy.da.SearchCursor
, SelectLayerByLocation_management
, arcpy.GetCount_management
, and arcpy.da.UpdateCursor
.
The code I have for this is currently updating all records for the Line_Count
field with the count of the point features (i.e. 2) for only the last record. Though, a print statement following the GetCount
line will return the line count for all of the point features (with a few unessential iterations). I believe it is only printing the last row in 'result' for the Line_Count
update statement. Is there an efficient way for result (i.e. result=int(arcpy.GetCount_management("tLayer_lyr").getOutput(0))
) to be saved as a list or an array that can be written to the Line_Count
field? …Or would it be best to use a dictionary?
What do I need to do to appropriately update the Line_Count
field for all of the records? Also, this process will be applied to a large dataset and will be extended to include 'where clauses'. Are there any suggestions as to how to make this as efficient as possible?
import arcpy
from arcpy import env
arcpy.env.OverwriteOutput = True
defaultGdbPath = 'C:\Topo_Check_Tess_V5.gdb'
sLayer='C:\Topo_Check_Tess_V5.gdb\Stations'
tLayer='C:\Topo_Check_Tess_V5.gdb\Lines'
#ppLayer='C:\Topo_Check_Tess_V5.gdb\Plants'
arcpy.AddField_management(sLayer, "Line_Count", "SHORT", "", "", "", "", "NULLABLE", "NON_REQUIRED", "")
TLineCountField = "Line_Count"
arcpy.MakeFeatureLayer_management(tLayer, "tLayer_lyr")
with arcpy.da.UpdateCursor (sLayer, TLineCountField) as LineCountList:
for s_row in LineCountList:
with arcpy.da.SearchCursor(sLayer,["OBJECTID", "SHAPE@"]) as s_list:
for station in s_list:
arcpy.SelectLayerByLocation_management("tLayer_lyr", 'WITHIN_A_DISTANCE', station[1],.000002, "NEW_SELECTION")
result=int(arcpy.GetCount_management("tLayer_lyr").getOutput(0))
print result
LineCountList.updateRow(s_row)
del station
del s_row
print "Done"
Best Answer
It is generally not an efficient approach (as several have commented) to use cursor processing in this way, but if you accept the performance hit (maybe you're not working with large feature classes), then you should at least eliminate the nested cursor. The update cursor can also be used as your 'read' cursor, so something like the following rewrite of your outer with block should work - this is untested: