What information does an index contour line carry?

What information does an index contour line carry?

• A. Elevation value along the line
• B. Temperature data
• C. Land ownership
• D. Road width

Answer: (A)

Index contour lines are the bold contour lines on a map that carry a labeled elevation value along the line. Every point on that line shares the same elevation, and the number printed on or near the line tells you that elevation. This labeling lets you read altitude quickly across the map and compare different areas by looking at how the labeled lines are spaced—the closer the lines, the steeper the slope. The other topics—temperature data, land ownership, and road width—aren’t conveyed by contour lines. Temperature is shown in climate data, ownership is shown by parcel boundaries, and road width is indicated by road symbols or notes, not by the elevation value of a contour line.