Wednesday, March 8, 2017

Map Coordinates and Lat/Long for Dummies (Again!)

comparing some basic map projections. UTM is cylindrical, but there are hundreds of other variations on these four and others.
map projection comparison
Considering how important maps are to anyone who doesn't want to get lost, you might think that the average person with even the slightest technical knowledge would have a good handle on them. You'd be wrong, though. Take, for instance, computer scientist Riz Khan of Leaf Group and Sciencing.com (the niche site for pseudoscience originally published at eHow): Riz was most certainly out of his depth when he penned "How to Convert Northing/Easting Coordinates to Latitude/Longitude."¹

Khan, given his degree in "computer information systems," decided that the appropriate answer would be to send people to a website. For starters, Riz told them that
"Northing/easting and longitude/latitude are two different ways of expressing geographical coordinates. If need be, however, the value from northing/easting can be converted to longitude/latitude, and vice versa. A number of online converters are available to assist you with the conversion."
We had to wonder if Khan and his content editor were unaware that northing/easting isn't "a value" but two values, and we quibble with the notion that those converters would "assist you" with your conversion: they'd just convert, not assist. Most of all, however, we were flummoxed by Kahn's assumption that there is only one system of projected coordinates: UTM.

Why, oh why, does everyone at eHow, errr, Sciencing think that there's only one coordinate system? Besides the fact that they're dumbasses who didn't spend enough time on research in their rush to pick up ten bucks? Rhetorical question, there...
   

Khan's solution, to meet the Demand Media requirement that he have three steps, was to send people to three different websites (two of which didn't make the transfer from eHow when Leaf Group created Sciencing.com). We found one of them, however, without much problem: the West Virginia EPA conversion site, which takes coordinates in either UTM or WV state plane. Dumbass Kahn instructed his readers to "Select the zone from the drop-down list"; all the while blithely ignoring the four West Virginia state plane options at the bottom!

Just for your information, Riz, there are dozens of different projection systems besides UTM, and a nearly infinite number of permutations and combinations of the parameters of those systems. For the real answer to that question, refer to the natural resources department of the local jurisdiction or just check out any Geographic Information System software (some of which is free).

     Heck, Khan even got what he published wrong, because he never mentioned the difference between northern and southern hemispheres in his post. So even if there were only one map projection and coordinate system, we'd probably still be giving Riz a Dumbass of the Day award.


¹ Leaf Group sent Khan's post to a rewrite specialist (we covered Kevin Beck's version here), but the original can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/how_8636452_convert-northingeasting-coordinates-longitudelatitude.html
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