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I have dabbled with ArcGIS and QGIS a bit, and I consider myself a self-taught beginner with a whole lot to learn.

So, I have two layers: 1) census blocks, and 2) point data.

My goal is to calculate the sum of the point data within the census blocks to eventually create a choropleth map and to run regression models with the sums of the points as a dependent variable; however, some of the points are directly between blocks and are not truly within them, so the points in polygons tool seems to miss a lot of points.

Because I am interested in the effect of these points on the proximal blocks, I had the idea of creating a 15m buffer around the points, and summing up the number of buffers that each census block intersected, but I am at a loss for how to do this in QGIS. So far, I have tried to join attributes by location, intersections, unions, and they all don't seem to get me where I need to be.

If anyone has an idea how to do this, I would greatly appreciate.

I attached a sample picture of my layout with the intersecting census blocks selected. Please excuse my labeling.

enter image description here

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Okay I figured it out.

  1. Make sure the coordinate reference system is the same for both the buffer layer as well as the census block layer.
  2. Select Vector > Data Management Tools > Join attributes by location.
  3. Set the "Target vector layer" to the buffer layer.
  4. Set the "Join vector layer" to the census blocks.
  5. Select the radio button for "Take summary of intersecting features"
  6. Deselect the "Mean" button and select the "Sum" button
  7. Specify the directory path for the output shapefile
  8. Select "Keep all records (including non-matching target records)"
  9. Click "OK"

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