Wednesday, January 18, 2017

Cartographic Skills Module 1: Map Critique

This assignment asked us to find and critique two maps, an example of a well-designed map and one of a poorly-designed map, judged on the basis of Edward Tufte's list of map design principles detailing what makes a good and useful thematic map.

As my well-designed map, I chose this one from the U.S. Census Bureau:



This map does a good job of clearly and concisely presenting the largest ancestry group in each county of the U.S., both providing that information for individual counties and visualizing regional patterns and variation. While there would surely be even more variation at an even smaller scale (such as census tract), using the county-level data brings out patterns that are hidden by state-level data without making the map so packed with information that it’s hard to see what’s happening. It follows Map Principle 2, “complex ideas communicated with clarity, precision, and efficiency;” it’s clear at a glance what the map is showing, and there is no ambiguity or unnecessary information. It also follows Map Principles 7 and 8 about clear and thorough labeling, by providing a prominent legend identifying the significance of each color displayed as well as a list of what’s included in the “Other” category. A few aesthetic aspects of this map that particularly appeal to me are its simplicity (there’s a lot of information presented because the map covers a large area, but it’s only two kinds of information, county outline and biggest ancestry group), its visual appeal (colors are readily distinguished from one another but none of them are blindingly bright or clashing with what’s around them), and the use of the ancestry by state inset map, which I think adds context and emphasizes the amount of variation at the county level.

As an example of a poorly designed map, I chose this one from mapsofworld.com:


The biggest problem with this map is that it supposedly shows countries according to language, but doesn’t explain what this categorization signifies. Are they mapping the majority language? The official language? Something else? Since many countries have multiple languages spoken within their borders, it’s important to be specific about what this map illustrates. While the layout and overall design of the map isn’t terrible, it’s hard to get any significant information out of it, which is a big problem. These issues are in violation of map principles 2 & 3, about clearly and efficiently mapping big or complex ideas, and possibly Principle 5, which “requires telling the truth about the data,” instead leaving the viewer with questions or assumptions about what the data actually mean. I would suggest improving this map by providing a clearer explanation (even a more specific title could potentially accomplish this) of what information is being presented, explaining or eliminating the inconsistencies in categorizing that information (e.g., what distinguishes countries labeled “multi-lingual” from those that have been assigned an individual language despite having multiple languages spoken by their populations, and why are some countries simply labeled “other”?), and being more careful with color choices to avoid confusion between very similar colors that mean different things.

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