Surveying, equipments used in surveying

 Surveying

Surveying is the art of making such measurements which will determine the relative positions of natural and man-made features on the surface

of the earth and plotting these measurements to some suitable scale to form a map,plan or section. In practice , however, surveying is often used

for determining positions of different features of earth in horizontal plane.

Leveling

Leveling is the art of determining and representing the relative heights or elevations of different points on the surface of the earth. Leveling is usually

used for determining positions of points in vertical plane.Surveying and leveling are frequently considered as distinct operations, however, the term surveying

includes leveling.

Differential leveling

This method is used in order to find the difference in elevation between two points i) if they are too far apart  ii) if the difference in elevation between them is too great

iii) if there are obstacles intervening. This process is also known as compound or continuous leveling.

Equipment used in surveying and leveling.

Measuring Tapes

Plastic tapes are now the most common type available for surveying and leveling. They usually come in lengths of 30 meters. Measurements not requiring a high degree of accuracy,such as dimensions

of existing bridge opening,short distance in cross sections and distances for strip cropping and orchard layouts are usually made with a tape.

Measuring Wheels

These are wheels of a known circumference mounted in a frame with a handle so that the wheel may be easily pushed along a line. The wheel is fitted with a trip meter which records the turns of the wheel over

a distance between two points. The trip meter usually measures to a tenth of a meter. The measuring wheel is useful method of obtaining the approximate 

length of a line.However, where the ground surface is rough, the accuracy of this method is significantly reduced.

Staff Rod

The staff rod is used for the purpose of measuring vertical distance.The width of black line is 0.01 meter (1 centimeter) and the width of the white space between black line is 0.01 meter.

The numbers on the face of the staff give the distance in meters from the bottom of the rod.

Ranging Rods

The ranging rod is a one or two piece pole usually 2 meter in length, painted red and white. It is generally used to establish a "line of sight"

Field book

 Engineering field books are used for the recording of survey notes and layouts. They are valuable documents because of the time and expense involved in obtaining such data.

Self Leveling Level-Dumpy Level

The self leveling level or dumpy level automatically levels its line of sight with great accuracy. It levels itself by means of a compensator after the circular spirit level is centered approximately. It is 

precise as well as simple and quick to operate. This instrument is used primarily for measuring vertical heights (elevations) of the points. However, horizontal distances and angles can also be measured by using this instrument.The parts of dumpy level are shown in figure.