Overview

Grid levelling determines the relative height of various points on, below and above the ground’s surface. It is a method to calculate the difference in levels or elevations between two points on the earth’s surface. Distance is measured from a reference point with known parameters. Grid levelling services help one to calculate the elevation of the given points with respect to the reference line or the datum that has been assumed or provided.

Various Types of Grid Levelling

Simple Levelling

This is very easy type of civil engineering levelling In this method, only one setting of the instrument is done. It is used for determining the difference of elevations of two points, which can be seen from a single position of the instrument.

Check Levelling

This type of levelling is done to check elevations, which have already been obtained. It is done at the end of each day’s work from the last station to the starting station for checking that day’s work.

Fly Levelling

This levelling is done to calculate approximate elevations of different points. It is done where rapidity but low precision is required. It is used for approximate checking of the levels or the reconnaissance of the area.

Profile Levelling

This type of levelling is done to determine the elevations of the ground surface along a fixed line. The levels obtained in this levelling are very useful for various profile levelling applications, such as determining the earthwork quantities, fixing the gradients, etc.

Differential Levelling

Various differential levelling techniques are used in this type of levelling. It requires more than one setting of the instrument. It is used when the two points are located quite apart. It is also called compound levelling.

Precise Levelling

Since precise levelling forconstruction is a precise method of differential levelling. It is employed when important work is to be carried out.

Cross-Section Levelling

This levelling is used to determine the difference of the ground surface along the line perpendicular to the centerline of the proposed road.

Application of Grid Levelling

• This levelling is used in civil engineering projects, such as roads, canals, bridges, etc. In addition, it is used to survey routes and alignment of bridges, highways, etc.
• Used for the purpose of earthwork, including cut and fills
• Used for pipeline route levelling to determine routes and provide maximum slope for the smooth flow inside pipelines
• Helps in preparing topographic maps and contour maps