Data Visualization’s ‘Dirty Little Secret’ and Choropleth Maps

The Washington Post’s Christopher Ingraham compares two choropleth maps of U.S. population growth: while they look rather different, they use the same data. “The difference between my map and Pew’s—again, they both use the exact same data set—underscores a bit of a dirty little secret in data journalism: Visualizing data is as much an art as a science. And seemingly tiny design decisions—where to set a color threshold, how many thresholds to set, etc.—can radically alter how numbers are displayed and perceived by readers.” [Andy Woodruff]

(Worth mentioning that this is exactly the sort of thing dealt with in Mark Monmonier’s How to Lie with Maps.)

People and Places

people-and-places Coming next month from Policy Press, the third edition of People and Places: A 21st-Century Atlas of the U.K. by Danny Dorling and Bethan Thomas. The Independent has a long profile of the book, which makes extensive use of cartograms to illustrate data about the British population, and one of its co-authors, Oxford geography professor Danny Dorling. Pre-order at Amazon (direct Amazon U.K. link—it’s more likely to be in stock there). [via]

Le Grand Paris en Cartes


Le Grand Paris en Cartes is a collection of interactive maps and infographics about the Grand Paris Express, a multi-billion-euro project to extend Paris’s Metro and rapid transit network deep into the surrounding Île-de-France region (if you can read French, the official site and French Wikipedia page provide a lot more information). These maps not only illustrate Parisians’ commuting routes and Metro usage, but also (see above) the kind of sociological data that underpins transit planning: employment centres, population density and so forth. In French. [via]

Mapping the Refugee Crisis


Here are two interactive maps that show the scale of recent refugee migrations. Lucify’s interactive map (screenshot above) shows the flow of asylum seekers to European countries since 2012. And this interactive map, compiled by The Conversation from UNHCR data, shows the size of refugee populations originating from or residing within each country from 1975 to 2010. In each case, the numbers grow with each passing year. More from Scientific American’s SA Visual blog. [via]

Mapping Aid Worker Attacks

An interactive map of attacks on aid workers since 2000. IRIN: “This map, a joint product between IRIN and Humanitarian Outcomes, is the first time ever the full scope of aid worker security events has been presented in visual form, which can be searched and filtered and browsed. It shows events from the beginning of 2000 until the end of May 2015. It’s a sobering testament to the dangerous work of saving lives.” [via]

Perpetual Ocean

Perpetual Ocean - Gulf Stream
You may have seen this already: a beautiful, painting-like visualization of the world’s surface ocean currents between June 2005 and November 2007, which NASA posted last month. The visualization is based on model data from the ECCO2 project. See also this short video on Flickr (Flash required). Image credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.