Which term describes the constant vertical distance between two contour lines?

• A. Contour interval
• B. Elevation band
• C. Gradient
• D. Elevation step

Answer: (A)

The fixed vertical difference between successive contour lines is called the contour interval. Contour lines connect points that share the same elevation, and moving from one line to the next increments elevation by this constant amount. The interval, shown in the map legend, stays the same across the map to give a consistent sense of relief and slope: lines that are close together indicate steeper terrain, while lines that are farther apart indicate gentler slopes. Elevation band describes a range of elevations shown by shading rather than the spacing of lines, gradient refers to the rate of elevation change over distance, and elevation step isn’t the standard term for this concept.