Define contour line and also contour interval.Describe the rules of contour lines.Synopsis of Contour Lines

Watch this video which defines many type of of the principles of contour lines. We will use many kind of of these principles in this module.

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Contour Lines and Contour Interval

Figure 6 shows a portion of a modern topographic map. The brvery own lines are contour lines.

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Figure 6. A portion of a topographic map, consisting of the contour interval label.

On topographic maps, each contour line connects points at the same elevation. The contour interval is the difference in elevation between adjacent contour lines.

The elevation for each contour line is sometimes marked on the line. To avoid clutter, not eexceptionally contour is labeled. The elevation of an unlabeled contour line can be determined by knowing the contour interval and looking at nearby contour lines. The elevation of a point situated in between two contour lines have the right to be estimated by interpolating in between the lines. If a point is halfmeans between 2 contour lines, it will certainly be around halfmeans between the elevations of those two contour lines.

In the US, conventional topographic maps have elevation noted in feet above suppose (average) sea level. However before, global maps and also maps of elevation of the ocean floor (bathymetry) are frequently noted in meters.

Tbelow are a pair of clues that will certainly aid you recognize the elevation devices on a map. First, the legend or information roughly the rim of the map might say something prefer “contour interval = 20 feet” or “contour interval = 20 meters.” Maps that usage systems of feet for elevation may note contour lines with systems such as 400′. The ‘ shows devices of feet.


Rules of Contour LinesEextremely point on a contour line is of the specific exact same elevation. In other words, contour lines connect points of equal elevation.By interpretation, contour lines separate points of better elevation from points of lower elevation. This indicates it is always possible to define an “uphill” direction on one side of a contour and also a “downhill” direction on the other side.Contour lines never cross.  They might come exceptionally cshed to each various other (e.g. alengthy a cliff), but by interpretation they might never cross each various other.* This is because one place on the surface of Earth cannot be at two various elevations!Contour lines never split. Instead, contours form closed loops. These loops follow the shape of the land also, and also might extfinish previous the edge of the map.Closely spaced contours suggest a steep slope, whereas contours that are spaced far acomponent show a gentle slope or virtually flat surconfront.

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Figure 7. An INCORRECT topographic map.