A gentle slope on a topographic map is shown by what contour line spacing?

A gentle slope on a topographic map is shown by what contour line spacing?

• A. Widely Spaced Contour Lines
• B. Closely Spaced Contour Lines
• C. Dotted Contour Lines
• D. Bold Contour Lines

Answer: (A)

Contour line spacing reflects how steep the terrain is. When the slope is gentle, elevation changes from one line to the next occur over a longer horizontal distance, so the lines are spread farther apart. If the slope were steeper, the same vertical change would happen over a shorter horizontal distance, causing the lines to crowd together. Dotted lines aren’t a standard indicator of slope, and bold (index) contours are just thicker lines used to label elevations, not to show how gradually or steeply the land rises. So the gentlest slope is shown by widely spaced contour lines.

Contour line spacing reflects how steep the terrain is. When the slope is gentle, elevation changes from one line to the next occur over a longer horizontal distance, so the lines are spread farther apart. If the slope were steeper, the same vertical change would happen over a shorter horizontal distance, causing the lines to crowd together. Dotted lines aren’t a standard indicator of slope, and bold (index) contours are just thicker lines used to label elevations, not to show how gradually or steeply the land rises. So the gentlest slope is shown by widely spaced contour lines.