Gts Benchmark Survey of India

A G.T.S. ( Great Trigonometrical Survey)  benchmark is a permanently fixed reference survey station (or point), having known elevation with respect to a standard datum (mean sea level). These are established all over India by Survey of India department with greater precision. A benchmark value is quite essential at any survey area, especially for reduction of observed sea level with respect to mean sea level or chart datum (CD). While carrying out bathymetric survey of a survey area, the datum referenced values thus obtained are used to compute the final depth contours of the survey area (with respect to CD). So, a benchmark, having known elevation is quite essential at the survey area, without which, preparation of a bathymetric chart is impossible. In some places, GTS benchmarks are available within a kilometer distance and can be easily transferred to the survey area by fly leveling using an automatic Level instrument and a graduated leveling staff. But in most of the cases, GT...