Topographic Maps, the Dummy Version

Map legend showing contour interval
(Elton, LA, 7.5-minute quadrangle)

Just about every day, we at the Antisocial Network run across yet another freelancer holding forth on a topic about which he or she knows nothing, and getting paid fairly well for doing so (otherwise they probably wouldn't). The most frequent offenders are the hacks over at eHow.com, a cornucopia of misinformation that somehow managed to stay solvent through the Panda update. Don't ask us how... Today's example of rampant incompetence is the site's Lillian Teague, here misinforming her readers on the topic of "How to Determine Vertical Scale."¹

Lillian, like most of eHow's dummies, began revealing her lack of knowledge on the topic in the introductory paragraph:

"All maps have a horizontal scale, the distance represented on the map by a specific measurement. For example, 1 inch may equal 100 miles. Topographic maps feature a vertical scale in addition to the horizontal scale."

Well, no, Lillian: topographic maps don't "feature a vertical scale," they have a contour interval. Despite which you said,

"Locate the map legend that lists the contour change. It looks like a typical horizontal scale legend, but it is labeled as the contour interval..."

A contour interval is not a vertical scale. In fact, maps don't have vertical scales, because maps represent horizontal areas. If you want to see a vertical scale, you have to look at a cross-section (or a graph, which is probably what the OQ wanted to know, moron). Not content with just starting off with ordinary dumbassery, Ms Teague continued to demonstrate her unfamiliarity with her topic by compounding her stupidity with statements like

"...Four intermediate contours can be found between each index contour..."

which is a rule of thumb only for (typical) USGS topographic maps, but not a universal constant of contour maps, because -- gasp! -- USGS topographic maps are not the only kind of map that uses contours!!!  and "[a contour interval of] 40 feet... is common on a 7.5-minute quad map" which is simply stupid. The contour interval of a map is a function of both the horizontal scale of the map and the range of elevations in the area. The area within a 7.5-minute quadrangle map of the Gulf Coast, for instance, may not even have forty feet of total elevation change (see example above). That would render a 40-foot contour interval useless.

For holding forth on a topic about which she knows nothing and for the mortal sin of attempting to redefine the term "contour interval" as "vertical scale," the Antisocial Network hereby designates Lillian Teague today's Dumbass of the Day. Sadly, we would be remiss if we did not point out that, in some cases, Lillian simply parrots oversimplification and misinformation she collected in her "references" - idiots, all...

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. The URL was ehow.com/how_6581486_determine-vertical-scale.html

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