← Methods 3

In-class Exercises

Choropleth maps and counting points in polygons

  1. Open the Council District Boundaries shapefile in QGIS.
  2. Open the NYPD Motor Vehicle Collisions file in QGIS.
  3. In the search bar in the bottom left of QGIS, search for "count points in polygon". Double-click the matching option under Processing Algorithms.
  4. Ensure the council districts are selected for Polygons, collisions are selected for Points.
  5. Click Run. This will take a minute or so.
  6. Once the count is complete, click Close to close the dialog.
  7. Style the new layer (likely named Count) with a graduated style using NUMPOINTS as the column.