Define edge line and also contour interval.Describe the rule of contour lines.Overview of edge Lines

Watch this video clip which explains plenty of of the ideas of edge lines. We will use many of these principles in this module.

You are watching: Why do contour lines never cross?

Contour Lines and also Contour Interval

Figure 6 mirrors a part of a contemporary topographic map. The brown lines room contour lines.

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

On topographic maps, each contour line connect points at the very same elevation. The contour interval is the difference in key between surrounding contour lines.

The elevation because that each contour line is sometimes significant on the line. To stop clutter, not every edge is labeled. The elevation of an unlabeled edge line can be determined by discovering the edge interval and also looking at surrounding contour lines. The key of a allude located in in between two contour lines can be approximated by interpolating in between the lines. If a point is halfway in between two edge lines, it will certainly be around halfway in between the elevations of those two contour lines.

In the US, standard topographic maps have actually elevation significant in feet above mean (average) sea level. However, worldwide maps and maps of elevation of the ocean floor (bathymetry) room often significant in meters.

There are a pair of hints that will help you determine the elevation systems on a map. First, the legend or information about the pickled in salt of the map may say something choose “contour interval = 20 feet” or “contour interval = 20 meters.” Maps the use units of feet for elevation may note contour lines through units such as 400′. The ‘ shows units that feet.

Rules of contour LinesEvery point on a contour line is that the exact same elevation. In other words, contour lines affix points of equal elevation.By definition, contour lines separate points of greater elevation native points of reduced elevation. This means it is always possible to specify an “uphill” direction on one next of a contour and a “downhill” direction ~ above the other side.Contour lines never cross.  They might come really close come each other (e.g. Follow me a cliff), but by meaning they may never cross each other.* This is because one ar on the surface of planet cannot be in ~ two different elevations!Contour lines never ever split. Instead, contours kind closed loops. This loops follow the form of the land, and also may prolong past the sheet of the map.Closely spaced contours suggest a steep slope, whereas contours that room spaced much apart suggest a gentle slope or practically flat surface.

See more: Difference Between .Java And .Class, What Is The Difference Among

Figure 7. An untrue topographic map.