Get Building A Topographic Map From Benchmarks Use The Benchmark Points To Draw Contour Lines

0:34 3:47 How to Read a Topo Map - YouTube YouTube Start of suggested clip End of suggested clip Spend. Some time with a map of a familiar area and see if you can pick out terrain features just byMoreSpend. Some time with a map of a familiar area and see if you can pick out terrain features just by looking at the contour. Lines.

“A benchmark, abbreviated “BM,” is a location whose elevation and horizontal position has been surveyed as accurately as possible. Benchmarks are designed for use as reference points, and are usually marked by small brass plates.”

You can find distance on the bar scale at the bottom of a topographic map. Marked points of precisely measured elevation, called benchmarks, are shown on topographic maps as “BM,” followed by the elevation in feet.

The distinctive characteristic of a topographic map is the use of elevation contour lines to show the shape of the Earth's surface. Elevation contours are imaginary lines connecting points having the same elevation on the surface of the land above or below a reference surface, which is usually mean sea level.

1:50 3:59 Once we've located the x's. Then we can draw a smooth curve through all of the points. Like so andMoreOnce we've located the x's. Then we can draw a smooth curve through all of the points. Like so and after we've drawn the contour line we need to make sure that we label it with its. Value.

In surveying, a benchmark -- or bench mark or survey benchmark -- is a post or other permanent mark established at a known elevation that is used as the basis for measuring the elevation of other topographical points.

Index contours are bold or thicker lines that appear at every fifth contour line. If the numbers associated with specific contour lines are increasing, the elevation of the terrain is also increasing. If the numbers associated with the contour lines are decreasing, there is a decrease in elevation.