A contour line is a line which defines a form or an edge. It is, essentially, the outline or silhouette of a given object or figure. Additionally, contour lines can be used to show any dramatic changes of plane within the object or form (like the inner seams within the structure of a shoe, for example).
A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value.
Topographic maps also have a vertical scale to allow the determination of a point in three dimensional space. Contour Lines: Contour lines are used to determine elevations and are lines on a map that are produced from connecting points of equal elevation (elevation refers to height in feet, or meters, above sea level).
There are 3 kinds of contour lines you'll see on a map: intermediate, index, and supplementary.
The thin brown lines snaking around a topographic map are called contour lines. All points along the same contour line are at the same elevation above sea level.
Other characteristics of contour lines are:
- Uniform slopes have uniformly spaced lines. - Along plane surfaces, contour lines are straight and parallel. - Contour lines are perpendicular to lines of steepest slopes. - For summits or depressions, contour lines most close upon themselves.
