Contour Lines Each thin, brown line represents a single elevation. Check the bottom corner of your map for the contour interval, which tells you how many vertical feet apart they are from one another (usually 40 feet). Thicker lines, or “index lines,” are labeled with the elevation in feet.
A. Steep terrain
Crowded sections of contour lines
B. Gradual terrain
Spacious sections of contour lines
V-shaped contour lines “point” toward higher elevations.
V-shaped contour lines “point” to lower elevations.
Black, dashed line
H. Dirt road
Black, dashed double-line
I. Railroad tracks
Solid black line with hatch marks
Solid blue line
Single blue hatch intersecting a stream
Contour line forms a small circle.