Saturday, 25 February 2017

Chain Survey

Chain survey is the simplest method of surveying. In this survey only measurements are taken
in the field, and the rest work, such as plotting calculation etc. are done in the office. This is
most suitable adapted to small plane areas with very few details. If carefully done, it gives
quite accurate results. The necessary requirements for field work are chain, tape, ranging rod,
arrows and some time cross staff.
Survey Station:
Survey stations are of two kinds
1. Main Stations
2. Subsidiary or tie
Main Stations:
Main stations are the end of the lines, which command the boundaries of the survey, and the
lines joining the main stations re called the main survey line or the chain lines.
Subsidiary or the tie stations:
Subsidiary or the tie stations are the point selected on the main survey lines, where it is
necessary to locate the interior detail such as fences, hedges, building etc.
Tie or subsidiary lines:
A tie line joints two fixed points on the main survey lines. It helps to checking the accuracy of
surveying and to locate the interior details. The position of each tie line should be close to
some features, such as paths, building etc.
Base Lines:
It is main and longest line, which passes approximately through the centre of the field. All the
other measurements to show the details of the work are taken with respect of this line.

Check Line:

A check line also termed as a proof line is a line joining the apex of a triangle to some fixed
points on any two sides of a triangle. A check line is measured to check the accuracy of the
framework. The length of a check line, as measured on the ground should agree with its
length on the plan.