Geospatial Data and Analysis

Chapter 3. Getting Started with Map Tools and Types

In 2015, mapmaker Benjamin Hennig assembled a collection of thematic maps—maps designed to illustrate a theme—for Geographical. To create them he used data from the International Union for Conservation of Nature’s Red List, an open data resource. Perhaps the most interesting part of the project was not the themes (as the topics were common), or even the dynamism of the maps (as they were static prints), but the form chosen for representing the data. Hennig chose cartograms, a fairly controversial approach to mapping that warps the forms of polygons according to the dataset you have, such that a country or administrative district with a higher density of x or y counts will appear larger in the resulting map. In Figure 3-1, countries proportionally bloat according to local animal and plant extinction threats. The larger “bloated” polygons have a higher density of species (plant/animal) at risk for extinction.

You can build cartograms using desktop tools with cartogram plug-ins like ArcGIS or QGIS. Although these tools are readily available, before using them you should consider some of the many open questions that surround the application of cartograms. These types of maps are controversial mostly because of how they distort geographic “reality”: they warp the spatial integrity of known maps, and may distort the resulting visualization so much that a geospatial representation seems unnecessary. Their popularity in articles and ...