# Calculating number of polygons or points that a set of polygons intersect with in ArcGIS

I have a set of ~100 polygons in ArcMap 10.2.2 that were generated using the minimum bounding geometry tool.

I have a second set of ~800 polygons generated the same way. What I need to know is for each individual polygon in set 1, how many polygons from set 2 does it overlap with.

I know I can use a tool like 'intersect' but this will produce a list of all unique combinations of overlapping polygons which would be a hugely cumbersome output for a 100 by 800 data set.

Is there a way to get ArcGIS to simply return the number of polygons that each polygon overlaps with rather than a huge list of all unique intersections?

• If you have workstation Arc/Info, you can use REGIONPOLYCOUNT, a useful command that never lived past 1999. Commented Jun 21, 2018 at 18:52
• 80k rows is trivial to GIS. I regularly process tens of millions of points against hundreds of thousands of polygons, and usually don't have time to walk up the hall before the query is done. Commented Jun 22, 2018 at 2:35
• Thanks for the suggestion, Kirk. And Vince, thanks for the encouragement (?). Unfortunately, on my laptop I would need a verrry long hallway. I have an intersect that has been running for awhile now and has written 100k rows. Commented Jun 22, 2018 at 11:37

I think you want to use Spatial Join if all you need is a count. This will allow you to input your 100 polygons as the input and the 800 as the join. You can specify that you only care about the count.

I would suggest trying this approach I came across from another post.

Using the intersect tool, you can then use the results found in the attribute table in the FID field to then form a Relate. Then you compare the Intersect results layer back to the original layer.

Here are the steps you might follow:
1. Intersect tool on the source layer;
2. Use the resulting layer to the source layer, based on the FID_ and OBJECTID columns respectively;
3. Select all records in the resulting layer;
4. In the attribute table of the resulting layer, use the Related Table button to select the related shapes: these are the original shapes, as wanted.

Documentation on:

Joins and Relates

Fundamentals of Object Fields