Measurement of distances using chain or tape is termed as chaining. This is the accurate and commonly employed method in surveying: These instruments can be classified as (i) chain (ii) steel band and (iii) tapes. (i) Chains: The chains are composed of 100 pieces of 4 mm diameter galvanised mild steel wires bent into rings at…
All the distances required for making a plan are the horizontal distances. Hence in the field horizontal distances are measured or sufficient readings are taken to calculate horizontal distances. In this chapter the methods used for linear measurements are explained. Method of preparing a plan using only linear measurements is by conducting chain surveying. METHODS…
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 centimetres and decametres are discouraged. Of course major difference between…
As stated in the definition of surveying the objective of measurements is to show relative positions of various objects on paper. Such representations on paper is called plan or map. A plan may be defined as the graphical representation of the features on, near or below the surface of the earth as projected on a…
To get accurate results in surveying one should follow the following fundamental principles: (i) Work from whole to part (ii) Take extra care in fixing new control points. Work from Whole to Part In surveying large areas, a system of control points are identified and they are located with high precision. Then secondary control points…
The earth is an oblate spheroid, length of equatorial axis being 12756.75 km and polar axis being 12713.80 km. Since the difference between these two axes and irregularities on the earth surface are very small (Note. Height of Mount Everest is 8.79 km) compared to these two axes, the earth may be treated as a…
As stated in the definition, object of surveying is to show relative positions of various objects of an area on paper and produce plan or map of that area. Various uses of surveying are listed below: (i) Plans prepared to record property lines of private, public and government lands help in avoiding unnecessary controversies. (ii)…
Surveying is the art of making measurements of objects on, above or beneath the ground to show theirrelative positions on paper. The relative position required is either horizontal, or vertical, or both.Less precisely the term Surveying is used to the measurement of objects in their horizontal positions. Measurements to deteremine their relative vertical positions is known as levelling.
Although there are many EDM instruments available, there are basically only two methods of measurement employed, namely the pulse method and the more popular phase difference method. Pulse method A short, intensive pulse of radiation is transmitted to a reflector target, which immediately transmits it back, along a parallel path, to the receiver. The measured…