Topographic Survey

Topographic survey involves determining the horizontal and vertical locations of objects on the surface of the earth. Horizontal location entails locating ‘objects’ like roads, railways, ponds, houses, boundaries of properties, etc. by measuring horizontal distances; the objects are indicated by symbols. Vertical location includes the location of hills, valleys, depressions, benchmarks, RLs of points, etc. by measuring vertical distances; the objects in this case are represented in relief. Thus, a topographic map shows the nature of the earth surface along with the positions of different objects. Such a map is essential for the engineering projects involving roads, railways, irrigation, reservoirs, townships etc. The scale of a topographic map depends on the extent of area it covers, and the purpose for which it is to be prepared. Generally topographic map is prepared according to a scale of 1 cm to 1 km (i.e. 1/100,000).