Topographic Map Reading
When I was learning how to read topographic maps, I developed a little memory heuristic to help remember the difference between contour lines that were going uphill versus those that were descending. I shared this with a hiker on one of my backpacking trips recently and it really helped them understand what the lines mean on a topographic map, so I thought I’d pass it along.
Let’s look at an example. This is a topographic representation of a hill. If you walk in the direction of the red arrow, you cross contour lines that are shaped like a frown, which frequently means you are going downhill.
This is Mount Lafayette in New Hampshire and here’s the topographic map for it from the National Geographic Topo DVD.
Descending Mt Lafayette
If you walk in the direction of the arrow, you will intersect contour lines that are shaped like a frown. While you’ll often be going downhill when this happens, you should still check the elevation markings (numbers) on the contour lines to see if they are descending or ascending, to be sure.
Not a frown, but still going down
As you can see, the contour lines at the point of the V shape are very close together which indicates a steep elevation grade. If you trace the contour lines out from the point of the V you’ll see that they are frown shaped as they approach each other, although it’s a little harder to see their curve until you move father away from the point where they intersect.
Lakes and Valleys
In this case, if you walk in the direction of the arrow, you will be crossing frowns but going uphill. You can determine this because the 3000 foot contour line is outside or beyond the 2800 foot contour, indicating an ascent if you walk in that direction.
Here’s what East Pond looks like, to help you match the symbols on the map to the actual landscape. As you can see, the landscape forms a saddle between two high points. The best advice I have to give in situations like these is to be sure to check the contour elevations when reading your map, to double check your interpretation of the topographic map you’re using.