Difficulty: Easy
Correct Answer: contour line
Explanation:
Introduction / Context:
Contour mapping is central to civil engineering design for roads, canals, embankments, and drainage. Understanding the precise meaning of contour-related terms helps in interpreting maps and preparing longitudinal and cross sections for earthwork computations.
Given Data / Assumptions:
Concept / Approach:
A contour line is the locus of points with the same elevation relative to a chosen datum (e.g., mean sea level). On maps, these lines depict terrain relief; close spacing means steep slopes, while wide spacing indicates gentle slopes. By contrast, a contour surface is the three-dimensional surface itself; a contour gradient is a line with a constant slope on the ground; and a level line is a line everywhere perpendicular to the direction of gravity (equipotential) and, strictly speaking, curved with the Earth.
Step-by-Step Solution:
Verification / Alternative check:
Any standard topographic sheet shows multiple contour lines labeled by elevations; interpolating between them estimates ground levels and slopes.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
contour line
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