topic Re: Spatial Join - join features to only one target in ArcGIS Pro Questions

Spatial Join - join features to only one target

faoiltiama — Tue, 29 Nov 2022 10:01:00 GMT

I would like to make a spatial join and use every join feature only once.

Current Input

Layer1 = Lines of road segments --> Target Features
Layer2 = Point data of accidents --> Join Features
Join Operation -->Join one to one
Keep all target features --> check
Match Option --> within a distance (25 Meters because the points are not perfectly accurate)

Wish

Spatial join should match every accident to one and only one road. Output should have a Join count with the number of accidents that happened on each road segment. Each accident should therefore be counted on the closest road segment.

Problem

The only thing that doesn't work until now is, that the accidents can be assigned to multiple road segments this way. How can I prevent this?

Re: Spatial Join - join features to only one target

DanPatterson — Tue, 29 Nov 2022 10:27:17 GMT

Are you using

Add Spatial Join (Data Management)—ArcGIS Pro | Documentation

which supports one-to-one

Spatial Join (Analysis)—ArcGIS Pro | Documentation

which supports one-to-many

Re: Spatial Join - join features to only one target

faoiltiama — Tue, 29 Nov 2022 13:59:47 GMT

I'm using the latter, Spatial Join (Analysis)

Re: Spatial Join - join features to only one target

JamesPoeschel — Mon, 25 Nov 2024 20:26:51 GMT

You can create a script tool for this.
You can rename the variable names if you like, in my case I was joining crashes to roads.

Here are the parameters:

And here is the execution code:

import arcpy import os # Define inputs and outputs crash_points = arcpy.GetParameterAsText(0) # Input crash points road_lines = arcpy.GetParameterAsText(1) # Input road lines output_feature_class = arcpy.GetParameterAsText(2) # Output feature class search_radius = arcpy.GetParameterAsText(3) # Search radius (e.g., "500 Meters") near_table = os.path.join("in_memory", "near_table") # Temporary Near Table try: # Step 1: Generate Near Table arcpy.AddMessage("Generating Near Table...") arcpy.GenerateNearTable_analysis( in_features=crash_points, near_features=road_lines, out_table=near_table, search_radius=search_radius, location="NO_LOCATION", angle="NO_ANGLE", closest="CLOSEST" # Only find the single closest feature ) # Step 2: Summarize crashes per road arcpy.AddMessage("Summarizing crashes per road...") summary_table = os.path.join("in_memory", "summary_table") arcpy.Statistics_analysis( in_table=near_table, out_table=summary_table, statistics_fields=[["IN_FID", "COUNT"]], case_field="NEAR_FID" ) # Step 3: Add crash counts (Join_Count) to roads arcpy.AddMessage("Joining crash counts to roads...") arcpy.MakeFeatureLayer_management(road_lines, "road_lines_lyr") arcpy.AddJoin_management( in_layer_or_view="road_lines_lyr", in_field="OBJECTID", join_table=summary_table, join_field="NEAR_FID" ) # Export joined features with crash counts arcpy.CopyFeatures_management("road_lines_lyr", output_feature_class) arcpy.AddMessage(f"Spatial join completed. Output saved to {output_feature_class}") except Exception as e: arcpy.AddError(f"An error occurred: {e}") raise

In my case, I only needed the join count per target feature. You may need to edit it if you need more information.