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Techniques for 1:1 spatial join where underlying data is 1:M

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03-25-2026 10:09 AM
Bud
by
Legendary Contributor
‎03-25-2026 10:09 AM

When performing a one-to-one spatial join, but the underlying data is one-to-many, such as one point to many polygons:

What are our options for handling the multiple polygons in the 1:1 join?

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1 Reply
Bud
by
Legendary Contributor
‎03-25-2026 09:06 PM

Here are the options I can think of so far:

  1. Control what related feature gets used:
    It's not documented, but Pro uses the related feature with the smallest OBJECTID for a one-to-one join. So, before doing the spatial join, we could use the Sort GP tool to sort the polygons so that the desired feature has the smallest OBJECTID.
    1. Related idea: Spatial Join — "One-to-one (tiebreaker field)" join operation
  2. Or, concatenate the polygon IDs into a text field using merge rules. 
    1. Spatial Join’s hidden trick on how to transfer attribute values in a One to Many relationship

Any other options?

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