How to Locate the Lowest Elevation

Locating the lowest elevation on a topographic map is actually one of the simplest readings that you can make on a topographic map. A topographic map is a map that not only tells you the location of certain landmarks in the area of the map but also the elevation of those landmarks through the use of lines. Every fifth line is marked with a number that represents the elevation so that you can easily read elevations.

Things You'll Need

  • Topographic map
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Instructions

    • 1

      Locate a marked elevation line on the topographic map. This is a line on the map that is has a number on it. For example the number 200 to represent an elevation of 200 feet above sea level. This will be your reference line.

    • 2

      Count five lines away from the marked line you found and see what elevation is marked on that line. Note that elevation lines can run in any direction, even circles so just count in whatever direction you want. Also note that not all markings will align so you might have to look for the marking on the fifth line away from your reference line.

    • 3

      Determine whether the elevation is moving up or down. If your reference line was 200 feet above sea level and the fifth line away is 100 feet above sea level, then the elevation is going down. If the elevation on the new line is 400 feet above sea level, the elevation is going up and you need to reverse your direction.

    • 4

      Continue looking at every fifth line in the direction of decreased elevation until you find the lowest elevation. Note that it is possible for there to be an elevation less than sea level. Sea level is 0 so you might have a negative elevation such as 10 feet below sea level.