what are the Procedure to Measure Area by Chain Triangulation in Chain Survey.

 

Procedure to Measure Area by Chain Triangulation in Chain Survey

Procedure:

• The sum of the areas of the three triangles is the area of the given field
• Let ABCDE be the given field whose area is to be measured, fix the pegs at A, B, C, D & E.
• Divide area into three triangles ADE, ABD and BCD by joining AD and BD.
• Measure the lengths AB, BC , CD, DE, EA, AD and BD.
• Calculate the area of the triangles.

• The sum of the areas of the three triangles is the area of the given field.

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Result:

The area of the given field = _______

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:

Base line is the main and longest line, which passes approximately through the center 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.

Offsets:

These are the lateral measurements from the base line to fix the positions of the different objects of the work with respect to base line. These are generally set at right angle offsets. It can also be drawn with the help of a tape. There are two kinds of offsets:

1. Perpendicular offsets
2. Oblique offsets

The measurements are taken at right angle to the survey line called perpendicular or right angled offsets. The measurements which are not made at right angles to the survey line are called oblique offsets or tie line offsets.