Surveying

Units of Measurements

According to Standards of Weights and Measurements Act, India decided to give up FPS system used earlier and switched over to MKS in 1956. In 1960 System International (SI units) unit was approved by the conference of weights and measures. It is an international organisation of which most of the countries are the members. In this system also unit of linear measurement is metre. However, in this system use of centimeters and decameters are discouraged. Of course major difference between MKS and SI is in the use of unit of force. In MKS unit of force is kg-wt (which is commonly called as kg only)
while in SI it is newton.

The recommended multipliers in SI units are given below

Giga unit = 1 × 10^9 units
Mega unit = 1 × 10^6 units
Kilo unit = 1 × 10^3 units
unit = 1 × 10^0 units
Milli unit = 1 × 10^–3 unit
Micro unit = 1 × 10^–6 unit

Commonly used linear units in surveying are kilometre, metre and millimetres. However centimetre is not yet fully given up.
For measuring angles sexagesimal system is used. In this system:

1 circumference = 360°
1 degree = 60′ (minutes of arc)
1 minute = 60″ (seconds of arc)

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