Understanding how to read a topographic map is a vital skill, even if you plan to bring a gps unit. Reading a map with confidence and accuracy can make the difference between an enjoyable experience outdoors or getting lost, and perhaps even life or death. Generally speaking, trail flyers or generic park maps are fine for short day hikes, but for longer hikes or backpacking trips it’s essential to carry and understand topographical maps. Follow this simple guide to learn everything you need to know about reading topographic maps.
What are topographic maps?
Topographic or “Topo”maps allow hikers and backpackers to conceptualize the 3-D terrain that surrounds them and lies ahead on their adventures.
What are Contour Lines on Topo Maps?
- Contour lines tell you about the terrain by indicating steepness and shape.
- Contour lines are connected at each end and every point on the line has the same elevation.
- The closer the lines are together the steeper the terrain and farther apart for more gradual terrain.
- Every 5th contour line is an “index line” which are labeled with elevation of the terrain.
- The contour interval refers to the elevation difference between two lines. Generally the contour interval is 40 or 80 feet. This can found in the map legend.
- Contour lines with ticks facing inwards indicate a decrease in elevation such as a depression.
Topo Map Scale
The scale of a topographic map indicates the detail of the map. For example a 1:24000 map scale means one inch equates to 24,000 inches or 2,000 feet of terrain. The larger the scale the more area covered but detail will be sacrificed.
Other General Topographic Map Features
- Green is used to indicate woods.
- Blue is used to denote water such as streams and lakes. Blue with dotted or cross-hatched interior means the lake is intermittent.
- Waterfalls are indicated by a blue hatch mark on a stream.
- Black dashed lines indicate trails and zigzag indicates switchbacks.
- Black double dashed lines indicate a dirt road. In general black denotes manmade features.
- Summits are found where contour lines form a small circle.
- Cliffs are very concentrated contour lines.
- Contour lines make a “V” it means one of two things, a ridge or a gully. If the “V” points towards higher elevations then it forms a gully. If the “V” points towards lower elevations then it indicates a ridge.