Add Spatial Join using Python

[Luca_Schikowski]

Hi there,

I am currently trying to work with python in ArcGIS Pro and I am stuck with the "Add Spatial Join"-Tool.

I got point-features (households) and lines (ducts) connected to them. I want to transfer some of the attributes from the households to the ducts feature class.

So first, I need to da a spatial join, right?

This is my code:

#code starts

import arcpy
import sys

def main():
arcpy.env.overwriteOutput = True

ducts = arcpy.GetParameterAsText(0)
houses = arcpy.GetParameterAsText(1)

try:
arcpy.AddMessage(f"Add Spatial Join:\n - Target-Layer: {ducts}\n - Join-Layer: {houses}")

arcpy.management.AddSpatialJoin(
target_features=ducts,
join_features=houses,
join_operation='JOIN_ONE_TO_ONE',
join_type='KEEP_ALL',
field_mapping='CID',
match_option='INTERSECT'
)
arcpy.AddMessage("Spatial Join Added successfully.")
except Exception as e:
arcpy.AddError(f"Error at 'Add Spatial Join': {e}")
if __name__ == "__main__":
main()

#code ends

When running this code, I get all the messages correctly and the tool finishes successfully but there is no spatial join added to my feature class. Is there an error in my code?

Thank you for your help!

Luca

[Bryan_bsc]

Hi Luca,

Unless your point features are exactly on the line features they won't intersect. I would try changing the match option from INTERSECT to CLOSEST. eg.

Cheers,

Bryan

[Luca_Schikowski]

Hi,

thank you, but the features are always directly connected.

[ModyBuchbinder]

Is the first parameter to the tool (ducts) a layer in pro or a FC on disk?

It must be a layer in Pro since the spatial join is on a layer and not on the real data.

You can always use the Gp tool once and then copy the code from the History window.

[Luca_Schikowski]

Hi,

so the code will only work, when the feature classes are actually added to the map in arc gis pro, right?

[AlfredBaldenweck]

Whenever you do anything involving a join or a selection on data, you need to make it a variable. otherwise, all the work gets done and then thrown into the ether.

This is my code:

#code starts

import arcpy
import sys

def main():
arcpy.env.overwriteOutput = True

ducts = arcpy.GetParameterAsText(0)
houses = arcpy.GetParameterAsText(1)

try:
arcpy.AddMessage(f"Add Spatial Join:\n - Target-Layer: {ducts}\n - Join-Layer: {houses}")

sjoin = arcpy.management.AddSpatialJoin(
target_features=ducts,
join_features=houses,
join_operation='JOIN_ONE_TO_ONE',
join_type='KEEP_ALL',
field_mapping='CID',
match_option='INTERSECT'
)
arcpy.AddMessage("Spatial Join Added successfully.")
except Exception as e:
arcpy.AddError(f"Error at 'Add Spatial Join': {e}")
if __name__ == "__main__":
main()

#code ends

You might have to add some lines telling it to actually add to the map, but I'd start with naming it and see what happens.

[Luca_Schikowski]

Hi, thank you!

When running your code, an error occurs:

I could not find the reason for this error. After some research it seems to be a syntax error. But why?

[AlfredBaldenweck]

Oh, that's my fault, sorry.

#code starts

import arcpy
import sys

def main():
    arcpy.env.overwriteOutput = True

    ducts = arcpy.GetParameterAsText(0)
    houses = arcpy.GetParameterAsText(1)

try:
    arcpy.AddMessage(f"Add Spatial Join:\n - Target-Layer: {ducts}\n - Join-Layer: {houses}")

    sjoin = arcpy.management.AddSpatialJoin(
    target_features=ducts,
    join_features=houses,
    join_operation='JOIN_ONE_TO_ONE',
    join_type='KEEP_ALL',
    field_mapping='CID',
    match_option='INTERSECT'
    )
    arcpy.AddMessage("Spatial Join Added successfully.")
except Exception as e:
    arcpy.AddError(f"Error at 'Add Spatial Join': {e}")
if __name__ == "__main__":
    main()

#code ends

 Any time you have a colon, the next lines have to be indented. 

[EdMorris]

Hi Luca

I'm not sure you managed to solve your spatial join problem? But what i do if i have a tool which doesn't work in a Python script is:

1: Find the tool e.g. Spatial Join, in the Geoprocessing pane

2: Run the tool using my inputs that I wish to pass into it from my Python script.

This generates a History item.

3: Display the History pane and locate your successful execution of the tool.

4: Double click the tool to display the tool's geoprocessing pane containing the parameter choices you made which ensured the successful run.

5: Click the dropdown arrow to the right of the pane's Run button and choose Copy Python Snippet.

This copies the Python code which ran the tool.

6: Paste the Python snippet into your script.

7: Change the hard-coded values generated by the Python snippet for your inputs, matching the data types.

Hopefully that should do the trick!

Have a look here for a more indepth discussion about various techniques you can use to get ArcGIS Pro to wrute Python code for you:

A simple way to get ArcGIS Pro to write arcpy geoprocessing python code 

I hope this helps you out.

Let me know how you get on.

thanks ed