topic Re: Large Point Feature Class: Fastest Way To Transfer Field Values From Overlapping Polygon in ArcGIS API for Python Questions

Large Point Feature Class: Fastest Way To Transfer Field Values From Overlapping Polygon

Philip_Sarnecki — Thu, 04 Sep 2025 09:08:01 GMT

I have a large point feature class (<2Mill features) and a polygon feature class consisting of multiple polygon features.

The points and polygons overlap.

I'd like to write the polygon field values into their overlapping point features.

Example:

Point feature A lies within polygon feature B -> Write respective value from polygon field "name" into point field "area_name".

What is the fastest way to do this with a python script?

So far i have tried two python scripts:

- Spatial Join (Intersect) -> Join the output with the point feature class -> transfer values using field calculator (from joined field "name" to field "area_name") -> remove join

- Iterate over the polygon (using cursor), in each iteration create a new layer of the current polygon (in memory) -> select overlapping points using location based selection -> write values into selected points

Both methods take too long.

I was thinking about using a Spatially Enabled Dataframe, would this get my task done faster?

Re: Large Point Feature Class: Fastest Way To Transfer Field Values From Overlapping Polygon

DanPatterson — Thu, 04 Sep 2025 09:53:41 GMT

How does a standard

Intersect (Analysis)—ArcGIS Pro | Documentation

Pairwise Intersect (Analysis)—ArcGIS Pro | Documentation

compare speed-wise?

You would get a new featureclass with both sets of fields. Rather than using a field calculator to update a field, perhaps deleting unnecessary fields might be faster (with a rename if it is really necessary)

Delete Field (Data Management)—ArcGIS Pro | Documentation

Alter Field (Data Management)—ArcGIS Pro | Documentation

Re: Large Point Feature Class: Fastest Way To Transfer Field Values From Overlapping Polygon

Philip_Sarnecki — Thu, 04 Sep 2025 10:30:43 GMT

Oh sorry, i forgot to mention, the original point feature class cannot be replaced. It may be edited but the file itself cannot be deleted or replaced

Re: Large Point Feature Class: Fastest Way To Transfer Field Values From Overlapping Polygon

JakeSkinner — Thu, 04 Sep 2025 10:51:36 GMT

@Philip_Sarnecki you may get better performance using an Update Cursor rather than the field calculator. Ex:

import arcpy pointFC = r"C:\temp\test.gdb\points" polygonFC = r"C:\temp\test.gdb\polygons" # Perform Spatial Join spatialJoinFC = arcpy.SpatialJoin_analysis(.....) # Create lookup dictionary nameDict = {} with arcpy.da.SearchCursor(spatialJoinFC, ["uniqueId", "area_name"]) as cursor: for row in cursor: nameDict[row[0]] = row[1] del cursor # Update point feature class with arcpy.da.UpdateCursor(pointFC, ["uniqueId", "name"]) as cursor: for row in cursor: row[1] = nameDict[row[0]] cursor.updateRow(row) del cursor

Re: Large Point Feature Class: Fastest Way To Transfer Field Values From Overlapping Polygon

Clubdebambos — Thu, 04 Sep 2025 13:10:34 GMT

Dictionaries and Update Cursors are also my preferred approach when updating a dataset based on another, avoiding joins and field calculator.