Summarize within between polygons

GeoKel

Hello,

I would like to calculate the amount of points outside of a 50 mile drive time polygon that I've created. I was wondering how I would best accomplish this with the Summarize Within tool or would the Summarize Nearby Tool be better? For more clarification, I would like the points that are both outside the 50 mile drive time polygon and within the US country border on my map to be counted. Any advice would be appreciated. 

 

-Kelly

AmandaRing

Hi @GeoKel,

Since you're looking to summarize features OUTSIDE of a polygon boundary, neither Summarize Within nor Summarize Nearby will be what you want, at least not without running a different tool first (more on that in a minute). Those tools are useful when you want to get information about features WITHIN particular boundaries.

When looking to find features outside a particular boundary, you could make use of the Erase capabilities within the Overlay Layers tool to remove the features that do fall within the boundary. This would leave you with only the features that are outside of the drive-time area.

If all you want is to find features that are both within one boundary (the Country border) and outside another one (the Drive-time polygon), I would suggest using the Find by Attributes and Location tool.
With that tool, you can combine multiple spatial operations in one tool.

For your case, you would set the query as follows:

Find features from: Kelly's points, then click to add a Spatial expression.

Where All of the following are true

Does not intersect Drive-Time polygons AND
Completely within US Country boundary

It should look similar to:

The result for this tool would be a point layer that is all the points that meet the criteria of being within the country border but not within the drive-time area (ex. points in blue below). Once you get that result, you could then simply look at the number of features as listed in the attribute table.

 

If you really wanted to make use of the Summarize Within tool's ability to calculate the count of features and statistics on those features, you would need to use a combination of Erase (through Overlay Layers) and Summarize Within. Here are the 2 possible workflows, which should both give you the same result:

A) Create "Zone of Interest" then summarize points within it.

1. Run Overlay Layers with the following parameters:

• Input features: US Country boundary
• Overlay features: Drive-time boundary
• Overlay type: Erase

2. Run Summarize Within with the following parameters:

• Input features: Kelly's Points
• Area type: Polygon layer
• Summary polygon layer: Result from step 1
• Add any field statistics that you want

The result from step 2 will give you a polygon layer with the count of points within that area and any statistics you specify.

Find the points outside the drive-time area and then summarize those that fall within the country boundary

1. Run Overlay Layers with the following parameters:

• Input features: Kelly's Points
• Overlay features: Drive-time boundary
• Overlay type: Erase

2. Run Summarize Within with the following parameters:

• Input features: Result from step 1
• Area type: Polygon layer
• Summary polygon layer: US Country boundary
• Add any field statistics that you want

Again, the result from step 2 will give you a polygon layer with the count of points within that area and any statistics you specify.

Hope that helps! Happy analysis 🙂