United States Search and Rescue Task Force
KNOW THE TERRITORY – TIPS ON TOPOGRAPHICAL MAPS
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When you are on a search and rescue mission, especially in wooded hills where the grade of the terrain may be the only distinguishing characteristic, a good topographical (topo) map can not only save you time, but can also prevent you from getting lost as well. Here are some tips on “decoding” a topo map.
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The brown contour lines on the map show the size and shape of hills and valleys. The closer the contour lines are, the steeper the grade will be.
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The contour index gives that line’s elevation above sea level. To see if the grade is uphill or downhill, scan the indexes.
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Check the scale (usually at the bottom of the map) to determine how large an area the map covers. In search and rescue, the most common (and best to use) map is 1:24,000. This means that 1 inch represents 24,000 inches. Likewise, on a 1:62,500 map, 1 inch would represent 62,500 inches or, about 1 mile of actual terrain.
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Contour lines form a “V” which can point out the flow direction of rivers and streams.
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As for color coding, blue of course means water. Green represents woods or thick vegetation and white shows fields.
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Also at the bottom of the map you will find the “Contour Interval.” It can read 20 feet, 40 feet, etc. This determines the elevation change between each pair of contour lines.
