The Surveyors House

What are Survey Stations and How to Select a Survey Station

 DEFINITION, HOW TO, FACTORS AFFECTING

Definition

Survey Stations is a point of importance at the beginning and end of chain line. There are two types of survey stations:

Main Station

• These are the end of survey line i.e. which connects boundaries.
• Line joining Main Stations is called Main Survey Line or Chain Line.
• They are represented by Circle, Capital letters A B... Or number 1 2... Or (A)

Subsidiary or Tie Station

• These are the points selected on main line, where it is necessary to run auxiliary lines to locate interior details such as corner, tree, building etc.
• Lines joining tie station are called Tie Lines or Subsidiary Lines
• They are represented by Small letters a, b,

Selection of Survey Station

The following points should be kept in mind while selecting a station:

• The stations should be mutually intervisible
• Main principle of chain survey should strictly be observed
• If possible, line through the whole length of area should be drawn
• All triangles should be well defined
• A check line should be provided in each triangle
• Survey lines should be as few as possible
• A number of tie lines should be drawn
• Position of survey lines should be such that to avoid obstacles to chaining and ranging
• It should be on level ground
• The sides of triangle should pass as close to the boundary as possible.

Important Lines

1. Base line
2. Check line
3. Tie line

Base Line

• The longest of the chain lines used in making a survey is generally regarded as Base line.
• It is the most important line because it fixes up the direction of all other lines, since on base line, is built framework of a survey.
• It should be laid on level ground, as possible through the center and length of the area.
• It should be correctly measured and should be measured twice or thrice.

Check Line

• A check line also called proof line is a line joining the apex of a triangle to some fixed point on the opposite side.
• A check line is measured to check the accuracy of the framework.
• Thus there is a complete check on the field measurement as well as on the accuracy of the plotting work.

Tie Line

• A tie line is a line joining fixed points termed as Tie station on the main survey lines.
• A tie line usually fulfill a dual purpose i.e. it checks the accuracy of the framework and enables the surveyor to locate the interior details which are far away from the main chain line