I made this up last fall. It's been collecting dust on the desktop. I thought I'd put it to use.
At the UNO October A meet in NH, the use of in slope lines in some places was very helpful, one might even say crucial - as in clarity versus confusion. The
first jpg shows a highlighted portion of the map with insufficient use of slope lines. There is a large hill in a larger reentrant under the right part of the oval. The
second jpg shows the first version of a short leg on the green course using the map as depicted in the first image. A runner going from 1 to 2 in the terrain climbs out of the depression, crosses a 20m wide ridge and drops into a reentrant where visibility was minimal (say 10m) due to dense pine trees. The runner might just expect to keep dropping (except the control description says “spur”). The
third jpg shows use of slope lines clarifying what is up and down (as well as circle cutting to better show the first depression). The
fourth shows the blue leg on the same day with the course line covering a crucial slope line (and part of another, halfway to #2) which had good reason to cause interpretation confusion especially with only a quick glance. This was an oversight on my part as course setter. I didn't think to look at everything covered by the lines connecting control point circles. The
fifth corrects the situation.
Slope lines aren't very often important in New England but in this piece of/type of terrain they were. Maybe they are the unsung heroes of the symbols legend. Details are endless in the pursuit of “perfection” and keeping competitors happy (or at least from complaining).
Of related interest perhaps, the copy of Birkhead sent me (next week's USOC meet map) has no slope lines. There are some earth banks (with tag lines) and one large depression but no slope lines per se. The addition of some would make sorting reentrant from spur a bit more speedy in some instances (for what it's worth). And might it not be beneficial for those with less contour reading experience?