Map Scales for Dummies

Different ways to express the same map scale

When it comes to geography, a lot of people seem to think they're experts because they can name the capitals of Slovakia and Belize (Bratislava and Belmopan, respectively). That's only partially true: after all, someone who wants to be an expert in geography needs at least passing familiarity with cartography; the more the better. We don't think eHowian Daniel Pinzow fit that particular bill, at least based on his Sciencing.com post "How to Create a Map Scale."

Pinzow's post is a rewrite of an earlier version that had been written by Risa Edwards, a version that had some good information and a pretty major error. Daniel's version, unfortunately, isn't much better. The first things get a little wonky is in his Step Number 1:

"Measure the Map and Two Locations: To create a scale, you must know the physical size of the map. Therefore, you must measure the length of the map. For example, if the map is 12 inches in length, partition the map into one-inch increments. Next, look up the specific distance as the crow flies -- a straight-line distance -- between two locations on the map."

We're sorry, Daniel: there is no need to measure "the length of the map," as that measurement has nothing to do with determining the scale of the map! Pinzow then went on to explain that, if

"The distance between New York City and Philadelphia on the map is exactly one inch [and the] actual straight-line distance between the two cities is 81 miles. The map scale would be 1 inch = 81 miles."

Notwithstanding the fact that a scale of 1" = 81 miles is rather bizarre, that's probably OK. But what if the distance were 1.62 inches? Pinzow didn't cover that... but we will: 81 miles / 1.62 inches = 50 miles/inch. Daniel then went on to babble about other types of scales, including something he called a verbal scale, explaining that,

"An example of a verbal scale is 1 centimeter = 30 miles."

Pardon our denseness, but isn't that pretty much the same thing as his first step (except for the bizarre mixture of metric and imperial units)? Finally, there's his notion of a "fractional scale":

"Using the above example, the verbal scale 1 centimeter = 30 miles would be written either as 1/30 or 1:30. Fractional scales are more difficult to use because the units are not provided."

No, Daniel, it wouldn't. And they aren't. It's just that you're rather stupid and don't know what you're talking about (sad, since Pinzow claims to have spent several years as a science teacher). In a scale stated as 1:30, any length on the map represents 30 of that same length on the ground: 30 inches, 30 feet, 30 furlongs, 30 cubits... Idiot.
It's sad, isn't it, that our Dumbass of the Day claimed to be a STEM expert!

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