Friday, July 18, 2014

Heights and contour lines

Heights can be indicated in FOUR ways on a topographic map.

1.     Contour lines - lines (brown) joining areas with the same height above sea level. The contour interval (difference between contour lines) on a 1:50 000 topographic map is 20m.
2.     Spot heights - indicated by a black dot and height value (in meters above sea level) of a specific point on a topographic map.
3.     Trig. beacons (triangulation station or trigonometrical point) - indicated by a triangle which shows its unique number and height above sea level up to one decimal of a meter.

A Trig. beacon

4.     Bench marks - indicated by an arrow pointing to a main road with the height in meters above sea level.




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