Maps with data, but that are not choropleths

Like line plots, map plots have limited utility. They can convey both data and location where the latter has relevance. The examples shown below illustrate placement of data on maps, but they are not choropleths, which are plots that color geographic regions by a gradient to convey some range. For instance, a choropleth of the United States might color each state according to its GDP per state, say with a very light green for the lowest states on that measure and a dark green for the highest states.

Foley Lardner Telemedicine 2017 [pg. 12] has included a simple map of the United States, where it applies only two colors to the states (indicating two-party consent or one-party consent). A list could have conveyed the same information as it is not apparent that geographic location has any bearing on the consent laws. This snippet includes the lower border line of the plot (called a ruler) and part of an icon in the upper right-hand portion of the page.

Another map shows up in DLA Piper Debt 2015 [pg. 15]. This one is actually an area plot with proportional circles superimposed on select countries of Europe. The same data could have been represented as a bar chart, but the map is more interesting to the eye.

DLA Piper RE 2017 [pg. 14] provides data on its respondent’s geographic profiles by means of an exploded-out map of the United States. The two jurisdictions that are not domestic regions, “International” and “Other,” tread water in the lower left.

Create a choropleth to display data by State, country, region

When legal managers want to present data by State or by country, they can make good use of what is called a “choropleth”.  Choropleths are maps that color their regions in proportion to the count or other statistic of the variable being displayed on the map, such as the number of pending law suits per State or amounts spent on outside counsel by country.   Darker colors typically indicate more in a region and lighter shades of the color indicate fewer.

Below is an example of a choropleth that appears in Exterro’s 2016 Law Firm Benchmarking Report at page 8.  It shows how many of the 112 survey participants come from each state.

exterro-choropleth-oct-2016-post

California is the darkest with 21; the grey states had no participants.  The table below the map, which is truncated in this screen shot, gives the actual numbers by State, so someone could carp that the choropleth sweetens the eye but adds no nutritional information.  Still, it looks pretty good and it is an unusual example of an effective graphical tool.