Orienteering Guide 05
Reading Topographic Maps
Map Reading
A topographic map shows both location and the shape of the land. It can reveal trails, roads, streams, ridges, valleys, slopes, summits, and other features that help a Scout plan a route and confirm position while traveling.
Read the map information first
- Map name and coverage area
- Map scale
- Contour interval
- Legend and symbols
- Coordinate system or grid information
- Publication or revision information
- Magnetic declination information, if shown
Scale
Scale compares distance on the map with distance on the ground. A common USGS 7.5-minute topographic map uses a scale of 1:24,000, meaning one unit on the map equals 24,000 of the same units on the ground. At that scale, one inch on the map represents about 2,000 feet on the ground. Always use the scale printed on the specific map in your hand.
Symbols and colors
Topographic maps use symbols, line styles, labels, and colors to represent real-world features. The exact symbol set can change between map products and publication periods, so the legend on the specific map is the final authority.
| Map feature | Common appearance |
|---|---|
| Water | Often blue, including lakes, rivers, streams, and other hydrographic features |
| Vegetation | Often green areas or patterns |
| Contours/elevation | Often brown lines; thicker index contours are labeled with elevation |
| Roads, structures, boundaries | Shown with different line styles, colors, and symbols depending on the map product |
| Trails and small features | Usually represented by specialized symbols explained in the legend |
Contour lines
A contour line connects points of equal elevation. The contour interval is the elevation difference between adjacent contour lines. Closely spaced contours indicate steep terrain; widely spaced contours indicate gentler terrain.
- Index contours are heavier lines labeled with elevation.
- Intermediate contours fall between index contours.
- Supplemental contours may be used to show smaller elevation changes.
- Closed contours can show hills or depressions. Depression contours use short tick marks pointing toward lower ground.
Recognizing terrain shapes
- Summit or hill: closed contours with elevation increasing toward the center.
- Valley or draw: contour lines form V or U shapes that generally point uphill or upstream.
- Ridge or spur: contour bends generally point downhill away from higher ground.
- Saddle: lower ground between two higher points.
- Steep slope: contour lines are close together.
- Gentle slope: contour lines are farther apart.
Measure route distance
For a straight segment, use the scale and a ruler or the ruler printed on a compass baseplate. For a winding trail, lay a piece of string along the route, then straighten and measure the string against the map scale. Remember that map distance does not automatically account for slower travel caused by steep slopes, brush, stream crossings, or rough ground.
