Count points in polygons per group in ArcGIS Pro

Question

I know that there are many similar topics around and I think I have checked them all but they all refer to different settings or aims.

My case is simple: I have

• polygons: building_blocks
• points: buildings (with a field called "type" indicating one of nine classes [basic, bungalow, villa, hall...])

I want to create pie charts from the building blocks indicating the fraction of the contained building types. Accordingly, I need the number of each of the nine building types as a separate column in the output polygon feature table.

The structure as I would need it (as table of the polygons, with BT= number of each building type)

I have tried the following tools:

• Spatial Join: Calculates the sum of points, but without distinguishing by "type"
• Aggregate Points: Has a Summary Fields option, but it doesn't group by "type"
• Count Overlapping Features: Has no group option

I know that it could be done with multiple steps:

1. select all points with building type 1
2. run aggregate
3. join the tables and add a new column for type 1
4. repeat with building types 2-9

But it is for a cartography course and I'm sure that this could be done easier (with two or three steps at least instead of 9)

Am I missing something crucial here?

I am using ArcGIS Pro 2.9.3 as a GIS Professional Advanced user.

Answer 1

You can achieve the table structure you require in 3 steps and then you can join that back to your polygon dataset.

So below is your starting scenario:

Step 1 - Join block ID to points. In ArcGIS Pro 3.0 you could use the new Add Spatial Join but the spatial join works just as well. So you are joining polygons to points thus the end result is a new layer where each point is tagged with its block ID.

Step 2 - Summarize your data as shown below.

This creates this output, it has all the information you require just not structured as you need.

Step 3 - Reorganize your table using the pivot tool, this is setup as shown below:

This creates this output:

Step 4 - Join this table to your polygon data and symbolize your pie charts.

Answer 2

Your first step should be to join the block IDs to the building points using Identity or Intersect. Then, you can run Frequency or Summary Statistics on the output using block ID and building type as the frequency/case fields to get a table whose rows will look like block ID | building type | number of buildings. (Rows will only be created for combinations of block ID and building type where at least one building exists.)

This table's format is not quite what you're looking for, so I would probably use the Pivot Table tool that @Hornbydd mentioned.