# How do you Aggregate a set of points that lie within different sections of a polygon?

I require some help with an ArcGIS 10.2.1 map that I am trying to create. I want to aggregate a set of points into bigger points depending on the number of those points that are inside a section of a polygon.

I have a shapefile with a set of points that represent service requests in New York City. I also have a shapefile that is a polygon of New York City divided up into different census sections. I would like to combine the individual points into larger points in relation to how many of those points are within a specified section of the polygon. I want to do this for each individual section of the polygon.

So that the resulting map will have one point for each section of the polygon. The size of the point will differ based on how many points were aggregated together to create that resulting point.

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## migrated from stackoverflow.comMay 12 '14 at 13:48

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Adding a simple picture with some points and sample of what your polygons look like would help one to understand the question better. – Alex Tereshenkov May 12 '14 at 15:55
If you have the advanced version of ArcGIS you could use the model found here: blogs.esri.com/esri/arcgis/2013/12/17/point-in-polygon-overlay – johns Oct 14 '15 at 12:55

Use "spatial join" to bring the point count into the polygon. You may need to add a field called count and use the field calculator to add 1 to all points in this field. In the spatial join choose the option SUM.

Now you have the sectional polygons with the count of point.

Now convert these polygons to points (check the inside button --most common--)

Now you have point with a count.

Use graduated symbols on the points and hey presto different sized symbols for each point in each polygon that represents the number of points in a sub poly.

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Something you might try is a different approach to the standard aggregate process. First, you could run a counting operation (points within a polygon) using spatial join. Next, convert the polygons to points (centroid). Lastly, symbolize those centroid points by Quantities/Graduated Symbols while setting Value to the count field of the centroids. The end result is a polygon centroid that has graduated symbology based on how many points fall within that polygon.

Counting Procedure: http://support.esri.com/cn/knowledgebase/techarticles/detail/30779

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