Questions: Reading Topographic Maps

Question 1

On a topographic map, where is the land steepest?

• A. Where the contour lines are farthest apart
• B. Where the contour lines are closest together
• C. Where the contour lines form a closed circle
• D. Where the contour lines have the highest labels

Answer: (B)

Each line marks the same change in elevation. When lines are packed tightly, the land rises a lot over a short horizontal distance, which means a steep slope.

Question 2

A map has a contour interval of 20 m. Point A is on the 340 m contour, and point B is on the 420 m contour. The two points are 2 km apart. What is the average gradient between them?

Model answer: The elevation difference is 420 − 340 = 80 m. Gradient = 80 m ÷ 2 km = 40 m per km.

Gradient is the change in elevation divided by the horizontal distance. Map units must be stated clearly; here the answer is 40 meters of rise per kilometer.

Question 3

Where a contour line crosses a stream, it bends into a V that points upstream.

• T. True
• F. False

Answer: True

A stream sits in a valley. Following one elevation line toward the stream, you must go up the valley to stay at the same height, so the line bends in a V that points uphill, toward where the stream comes from.

Question 4

A set of closed contour loops has short tick marks (hachures) on the inside of the innermost loop. What does this show?

• A. A hilltop
• B. A depression, such as a crater or sinkhole
• C. A lake
• D. A cliff

Answer: (B)

Plain closed loops show a hill. Hachure marks pointing inward show that the land goes down inside the loop, which is a depression.