Cape Town is running out of drinking water, a crisis dramatically depicted by NASA Earth Observatory maps that show the depletion of the city’s reservoirs. The animated gif above, for example, “shows how dramatically Theewaterskloof [Cape Town’s largest reservoir] has been depleted between January 2014 and January 2018. The extent of the reservoir is shown with blue; non-water areas have been masked with gray in order to make it easier to distinguish how the reservoir has changed. Theewaterskloof was near full capacity in 2014. During the preceding year, the weather station at Cape Town airport tallied 682 millimeters (27 inches) of rain (515 mm is normal), making it one of the wettest years in decades. However, rains faltered in 2015, with just 325 mm falling. The next year, with 221 mm, was even worse. In 2017, the station recorded just 157 mm of rain.”
The maps that appear from time to time on xkcd are usually a lot more whimsical than the one Randall posted today: his somewhat belated “2016 Election Map” assigns one figure for every 250,000 votes for each of the 2016 presidential election candidates. As Randall says in the alt text,1 “I like the idea of cartograms (distorted population maps), but I feel like in practice they often end up being the worst of both worlds—not great for showing geography OR counting people. And on top of that, they have all the problems of a chloro… chorophl… chloropet… map with areas colored in.” This is an issue that election map cartographers regularly have to deal with, as many of my readers know well.
I didn’t know Replogle made Christmas ornaments. I stumbled across the above, a Waldseemüller globe ornament—i.e., an ornament based on the Waldseemüller globe gores—while poking around my local map store for the first time in years. I bought the last one they had in stock. It’s 3¼″ (8.3 cm) in diameter, comes with a stand, and cost me all of $10. There’s apparently a Coronelli globe ornament as well.
Cartographers in the Field: “This Depression-era oil painting was created by USGS field man Hal Shelton in 1940. The painting depicts mapping techniques used in the early days of cartography, including an alidade and stadia rod for determining distances and elevations and a plane-table for sketching contour lines. A USGS benchmark is visible near the top. The straight white lines represent survey transects. Note the ‘US’ marking on the canteen: many of the USGS field supplies were obtained from Army surplus.” [Osher Map Library]
I’m surprised it took as look as it did for physics and cartography to collide—relativity and choropleth maps—in an xkcd cartoon.
In yesterday’s xkcd cartoon, Randall makes explicit what I think a lot of us have been thinking about those maps assigning a word or a search term to each state or country or whatnot.
Daniel Raillant-Clark’s map of Montréal’s Métro with anglicized station names (in most cases) is full of awful translations in both directions and puns in both languages (example: “Georges-Vanier” becomes “George Go Deny It” because va nier means go deny). To see what the hell this map is messing with, the real Métro map is here. [MTL Blog/Reddit]
Randall Munroe is a bad man who is back with another bad map projection to make our eyes bleed. (If he does this often enough he’ll have enough for a book. Heaven forfend.) This one is, like his other maps, fiendishly subtle: it stretches and compresses countries to fit where their time zones ought to be, longitudinally speaking.
Today’s xkcd is a British map labelled by an American. It’s another one of those where the longer you stare at it, the more it hurts. Randall’s messing with us again.