Contours are imaginary outlines used for connecting locations and places with the same elevation. They make it possible to present the steepness of slopes and the tallness of mountains on a surface printed on a two-dimensional map. One of the most significant characteristics of contour lines is that they model the 3D shape of the earth to a 2D model. Below are some of the facts you should know about topographic maps.
Close and Wide Spacing
Contour lines provide exact details of the earth’s surface using both close and wide spacing. On steep bluffs, they seem to be packed carefully to one another while they are spaced out in flat areas. They appear close to one another because elevation increases on sharp slopes. This happens with a higher frequency on every unit of horizontal distance on the map.
Do Not Intersect
One of the fundamental features of contour lines is they will cross, traverse, or branch. However, they may come close to touching but only on incredibly steep slopes. That may be due to the thickness of the final copy of printed contour lines. Always remember that the lines can only coincide with vertical slopes.
The interval of contour lines remains the same on every map. You should know that either the fourth or fifth line must be marked according to their elevation for more natural referencing. On real topographic maps, the lines are used for indicating 50 feet of elevation. All the elevations on the map are meant to imply sea level, which in most cases, is the ‘0’ foot elevation contour.
Rivers and Streams
Parallel lines usually indicate the vast rivers and streams by estimating their overall breadth. If you can see single blue lines, then know they are showing the narrow streams and creeks. Additionally, individual unlabeled lines show coastlines and lakeshores.