Various technical terms used in connection with the network of the triangles in surveying are explained below:
Station: Station is a point of importance at the beginning or at the end of a survey line.
Main station: These are the stations at the beginning or at the end of lines forming main skeleton. They are denoted as A, B, C etc.
Subsidiary or tie stations: These are the stations selected on main lines to run auxiliary/secondary lines for the purpose of locating interior details. These stations are denoted as a, b, c, …., etc., or as 1, 2, 3, … etc.
Base line: It is the most important line and is the longest. Usually it is the line plotted first and then frame work of triangles are built on it.
Detail lines: If the important objects are far away from the main lines, the offsets are too long, resulting into inaccuracies and taking more time for the measurements. In such cases the secondary lines are run by selecting secondary stations on main lines. Such lines are called detail lines.
Check lines: These are the lines connecting main station and a substation on opposite side or the lines connecting to substations on the sides of main lines. The purpose of measuring such lines is to check the accuracy with which main stations are located.
