How do map data and map design affect bias? Does it matter if the bias is intentional or not? Honesty is the cornerstone virtue of ethics. These considerations are discussed with respect to three specific political maps but the concepts are widely applicable to most mapping endeavors.
Maps and Links
USA 2016 MTC Election Map
Election time in the U.S. tends to be a fun and exciting time to watch newscasters point to maps on TV as they show election results. This particular election map shows counties in either a solid red or a solid blue color depending on the results of the 2016 presidential election. But counties vary in size greatly across the U.S. and herein lies the issue: a county that is quite large-in-size might have a few thousand people in it whereas a small-in-size county, on the East Coast for example, might have 40,000 people in it. The larger county carries more visual weight than the small one even though this does not reflect the number of voters in those counties. Historically, U.S. presidential maps were often shown this way, except for the occasional bulbous-looking cartogram, which is a type of map that distorts geography depending on numeric values within the geographic units [7:18].
Modern-day elections maps have been getting a lot better at showing the data in a more accurate way. In 2020, in particular, the U.S. election maps were highly varied. We saw some attempts at more diagrammatic maps like grids of states where each state was an equally sized square, which at least equalizes the geography. But some of the maps go further. For example, value by alpha maps use the correct geography but vary the alpha-channel, or transparency, of the blues and reds such that the color is more transparent where there are less people and more opaque where there are more people [8:50]. You can take the value by alpha map style even further by displaying the colors as a mixture of red and blue so that a place that is, for example, shown as purple, would indicate that there is more of a 50/50 mixture of votes for each party in that location.
Gerrymandering - The Atlas of Redistricting Article
Gerrymandering is the act of drawing a voting district boundary such that it includes just the right proportion of voters for a particular party to enable that party to benefit [14:34]. The Supreme Court ruled that both parties are at fault with respect to gerrymandering [15:22].
There is a concept in mapping called the Modifiable Areal Unit Problem (MAUP), where you have point data (in our case, with gerrymandering, these are really people points, or where those people live) that you are aggregating, and depending on where you draw your aggregation lines, you may get vastly different statistics out of the data [17:00]. In mapping, if the cartographer decides to re-draw aggregation units in order to make the map look a certain way that is inconsistent with the data, this would be an intentionally biased map [19:26]. Maps are authoritative documents, with the implication being that cartographers have a responsibility to ensure maps are designed as correctly as possible [21:10].
Note that the example at [23:22] would have been better if it had been laid out as splitting the Denver area into the same number of districts in both cases. If a party has a lot of rural voters it could be tempted to create districts that have small portions of the city and larger portions of rural areas (probably resulting in elongated districts) whereas a party that has a lot of city voters could be tempted to draw districts that included enough city dwellers to skew them toward that party.
Victory Through Airpower 1943 Video
This is an animated persuasive movie trailer that has a lot of visuals depicting dangerous things happening with respect to war. It evokes feelings via dramatic sounds and visuals. Maps have the power to persuade and do indeed do so in this video. The map that starts 12 seconds in on the trailer is animated in the sense that the Ken Burns effect is used to sweep the camera across an image. There are also animations on the map in the more traditional sense of the word animation; the edges of polygons move in order to draw attention to them. Note that it was incorrectly asserted in this segment that the map only animates once the camera gets to Japan, whereas in actuality it also is animated at the beginning of the camera sweep.
This may be one of the first instances of an animated map. In the second animated map in the video there are lines that move away from the U.S. on both coasts to emphasize that the U.S. is connected to other places in the world, thus trying to convince the viewer of the importance of these connections. There are many other propaganda map examples including one that featured an octopus [30:50]. We still have persuasive propaganda maps in our midst, though now they may be harder to detect in the sense that they may purposefully look like legitimate cartographic truths, and therefore learning how to think critically about maps is an important skill for everyone [31:02].