I would like to create a simple Dorling Cartogram map in QGIS. My goal is for it to be a similar style to these maps created by the New York Times:
I have a shapefile of jurisdictions, and I would like to size them based on their population. The shapefile already has equal-sized square polygons for each jurisdiction, with each polygon roughly placed in its correct geographical location relative to the other polygons.
The Cartogram plug-in in QGIS does a good job of creating a Contiguous Cartogram, but I would like to keep the square-shape of each polygon; just size them larger or smaller based on their population.
After they have been sized, I would also like to be able to do some basic styling on them (i.e. have different colored polygons based on the type of jurisdiction, like City, Village, etc.).
Best Answer
there are a couple of tools out there (ProtoViz, Mapresso) that can do this but they're no longer actively developed or supported.
I did find this d3 example on Bloc.ks which does a Dorling (or is it Demers?) Cartogram.
It uses force-directed graphing to jostle the states into a pleasing layout to minimise overlaps, although some overlaps still exist (shown as brown in that example).
If you have sufficient JavaScript knowledge you might be able to adapt that, or even code it to output the results as a shapefile or delimited WKT file.
The resulting Cartogram can be dropped into Map Composer as an HTML frame. You might be able to extract the SVG (d3 works as SVG) and import as an image too.