The most common type of theme map is a choropleth map. When geospatial data is linked to some enumeration units, they are extremely effective (Counties, provinces, districts, etc.). The distinct polygons inside a layer of a choropleth map have varying shades of colors signifying a specific property of that polygon (in our case, the number of locations). We’ll make a choropleth map for the United States, with each state’s color graded proportionately to its number of sites.

The main steps for developing the Choropleth map are:

• Importing the polygon vector map.
• Importing the CSV file as a point vecto
• Calculating the number of locations inside each state using the ‘Count points in’ tool.
• Editing the symbol for getting the Choropleth map
• Exporting map as an image or PDF.

Importing Polygon Vector Map

To create a Choropleth map, we must first obtain a country/region polygon vector map. A state in the United States is represented by each polygon in the vector map. Extract data from zipped folder by downloading the compressed shapefiles. By double-clicking on the.shp file in the Browser toolbar, you can add it to QGIS (or dragging and dropping).
SabineRyhner 18 october 2021, 12:50