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How can I aggregate pointdata in rastercells (as administrative units)

July 12 2011 | 1 comment
Categories: ArcGIS Methods, Map Data, Symbology

I am working with point data and polygons (raster). These data should be aggregated to one point in a raster cell (polygons). Which geoprocessing operation aggregates the points to one point? And how can I select the points in a raster cell to aggregate them to one point?

Mapping Center Answer:

First I will assume that you have converted your raster to polygons. If so, then here are the steps you can take:

  1. Use Intersect to determine which polygon each point feature falls within. The Input Features will be your point feature class and the feature class with the polygons that represent the raster cells. 
  2. Use Frequency to calculate how many point features have the same polygon id. The Input Table will be the new feature class created in the previous step, the Frequency Field will be the FID of the polys (probably the last field listed).
  3. Use a Join on the feature class with the polygons that represent the raster cells to determine how many features fall within each polgyon. The ObjectId is the field in the layer that the join will be based upon, the frequency table is the table to join to this layer, and the Cell_Id is the field in the table to base the join on.
  4. Symbolize the features – I used graduated symbols with FREQUENCY as the Value Field, a brown square as the template, eight classes and range of symbol sizes from 3 to 15 at a map scale of 1:150,000,000 for the world. Here is my result when I used this method to count the number of cities in my cities feature class within every 5 x 5 degree cell of the graticule:

Raster Cell Count Output

Another solution posted by Aileen Buckley on Jul 28 2011 11:00AM
Here is another solution that has been suggested:

1. Create Fishnet (polygons with label points option)
2. Then Zonal Statistics as Table for the zones (fishnet polygons)
3. Then join the table to the fishnet label points via Zone ID and assign graduated symbols based on the aggregated value.

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