High School Earth Science: Earth's Surface - Topographic Maps — Flashcards

A topographic map uses contour lines to show the three-dimensional shape of the land. Contour lines reveal the locations of hills, valleys, and other surface features. To read a topographic map, you should know that:
- Each contour line represents a specific elevation and connects all the points that have that elevation. Every fifth contour line is bolded and labeled with its elevation.
- Contour lines run next to each other but never intersect.
- Adjacent contour lines are separated by a constant difference in elevation, called the contour interval. The map legend gives the contour interval.
- Closely-spaced contour lines indicate a steep slope. They show that the elevation changes quickly over a short horizontal distance. Contour lines that seem to touch indicate a very steep rise, such as a cliff or canyon wall.
Broadly spaced contour lines, in contrast, indicate a gentle slope.
- Contour lines that form concentric closed loops indicate hills. Smaller loops represent higher elevations.
- Hatched concentric loops indicate depressions. Hatch marks are short, perpendicular lines inside a loop.
Smaller hatched loops represent lower elevations.
- A group of V-shaped contour lines indicates a stream valley. The narrow part of the Vs point uphill. Water always flows from higher to lower elevations, so the Vs also tell you the direction the water is flowing.