Reading a blog post by Jon Udell just now - Visual numeracy for collective survival - I came across this question: What do you call th[e] kind of [map] projection, where country size is proportional to a variable? What do you call something like this, for example? Any ideas? How would you search for it? I started off for a search on "proportional country map", and was lucky enough to soon hit upon an explanation by scanning through the search results: this type of map is called a cartogram, and it's one of several ways of using a map to depict the value of some particular measure or statistic.
Related: GeoVis Tools
• Data visualization