Topographic Maps

index contours

Every fifth line, known as the index contour, is darker and heavier than the others. They are labeled with elevation in round units such as 1,600 or 2,000 feet.

What do widely shaped contour lines represent?

Gentle slopes or flatter areas.

Many topographic maps are at what scale?

1:24,000 or 1cm = .24 km

contour line

A contour line on a topographic map connects points of equal elevation.

What does a contour line that forms a closed loop with not other contour lines inside it represent?

A hilltop.

topographic map

A map showing the surface features of an area.

What do V shaped contour lines pointing downhill represent?

A ridge.

What do V shaped contour lines pointing uphill represent?

A valley.

How do you determine the contour interval on a topographic map?

Determine the difference in elevation between the two dark index contour lines. Then, divide that number by the number of contour intervals between the dark lines.

What do closely shaped contour lines represent?

Steep slopes.

contour interval

The change in elevation from contour line to contour line is called the contour interval.

What do you need to know about a topographic map in order to read it?

The scale, the meaning of the map symbols, and the contour interval.

Mapmakers use contour lines to represent what three things on topographic maps?

elevation, relief, and slope