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I am using ArcGIS Pro.

I have a point feature with 3000 points and a polygon feature with 50 counties.

I want to calculate Number of points in each county and the Sum of the values of the points in each county, i.e I want as output a point feature with only 50 rows (the number of counties) with the fields "County", "Num" and "Sum" in it.

I am trying with Spatial Join tool, but I get again a 3000 rows output (I put the point as target and polygon as join).

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  • There's many ways. We often did different analyses in situations like this so as a matter of habit we'd run an intersect overlay of the points and polygons, copy and paste the table into Excel, make a pivot table doing whatever analyses we wanted , and then join that to the polygon layer. Once a habit things went fast. In any case when using the feature to point tool you may want to check the parameter to keep the point within the polygon; centroids can end up outside the polygon in some shapes.
    – John
    Commented 2 days ago

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As the 50 points do not exist you need to create them, the obvious would be the centroid of the county polygons.

  1. Create a field in your polygon dataset that gives each polygon a unique ID, don't rely on the ObjectID.
  2. Centroids can be easily created using the Feature to point tool. This creates the point with the unique ID.
  3. Do you spatial join setting the field mapping to compute the values you require but it is the polygon that is the TARGET. You will have a 1:many relationship, 1 polygon intersects may points.
  4. Join the output of the spatial join to your centroid dataset.
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    Why not using the 'feature to point' tool after joining the points to the polygon ( doing steep 1 - 3 - 2 in this order and not needing steep 4) ?
    – J.R
    Commented 2 days ago
  • @J.R optimising my workflow, nice! I guess it's just how I see the world, in 4 steps not 3.
    – Hornbydd
    Commented 2 days ago

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