Reading Topographic Maps for Dummies

Topographic map example

It's been a couple of weeks since we looked through our file of potential maps DotDs, which doesn't mean that we haven't forgotten the geographically illiterate freelancers out there. Sometimes we wonder how anyone can get anywhere without a little voice whispering in their ear. Heck, some of these people can get lost with a GPS whispering in their shell-like ear! We don't know whether eHowian Keri Honea would get lost with a road map, but we are pretty sure she shouldn't have written about "How to Read Topographic Maps" for Sciencing.com.

Certainly, it's pretty easy to find (and reword) the definition of a topographic map in many places around the Web. Honea managed, for the most part, to get that taken care of; although it's relatively easy to recognize her ignorance of the topic from sentence number one:

"A topographic map is a three-dimensional depiction (but usually in a two-dimensional presentation) of the contours and elevations of a region, such as mountains, hills, valleys and rivers."

A) a topographic map is always two-dimensional¹ and B) what Keri calls the "contours and elevations" is, in fact, topography. Moving right along, Keri informed us that,

"To read a topographic map, you need to understand the representations of the many circles and lines scrawled all over the terrain."

A), those lines aren't "scrawled," and B) the lines are on the map, not on the terrain. Wonder of wonders, Honea managed to correctly transcribe the fact that contour lines connect points of equal elevation, though she seemed a little confused about the contour interval in the legend:

"The map's legend will indicate the elevation distances between the contour lines."

It isn't a "distance," it's an elevation difference. If you want to know the distance between two lines, you merely measure it from the map. More confusion ensues as you attempt to decode Keri's instructions for interpreting contour patterns:

"Examine the loops formed by the contour lines. Inside the loops typically indicates uphill and outside indicates downhill."

We're sorry, Keri, but that makes no friggin' sense. Neither does this:

"Check for base elevation in the map legend. Topographic maps of mountain ranges may have a base elevation of 8,000 feet, so a topographic reading of 800 means the point of interest is at 8,800 feet."

That rubbish isn't in her reference, neither is it in any discussion of topographic maps we've ever seen. For that matter, neither is this:

"Check the water tables in the map legend."

The rest of the paragraph mumbles something about negative contour values, suggesting that Honea somehow decided that the elevation reference (Mean Sea Level) somehow had something to do with the local water table. You gotta be a Dumbass of the Day to be that clueless.

¹ There are, however, relief maps that are three-dimensional; which are sometimes called "topographic relief maps."

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