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Types and Benefits of Compass Surveying in Civil Engineering

Compass surveying is one of the important surveying processes that have been used to determine the position of objects. The determination of the object’s position has been done by using compass surveying by estimating the length and angles. In this case, the length has been measured with the help of a tape measure or a chain.

Areas in which compass surveying is highly preferred

• In the case of surveying a large area, for example, surveying the coastal or coarse areas of rivers, compass surveying has been used.
• In the case of triangulation is impossible and many obstacles are there for conducting a chain survey as the is crowded along with a lot of details, this type of surveying can be conducted.
• In the case of having a specific deadline for completing the survey procedure of a detailed and large area, the compass surveying technique can be used.

Benefits of using Compass Surveying

There are numerous advantages of using compass surveying techniques which include:

• These types of compasses are lightweight and portable.
• These types of compasses have fewer settings rather than other types of surveying techniques which is easy to fix on a station.
• This surveying process is appropriate for retracing the old surveying processes.
• The error in the direction that has been produced in a single survey line has not had any effect on the other lines.

Different Types of Compass Surveying

There are numerous types of compass surveying which include:

• Magnetic Compass
• GPS compass
• Gyro Compass
• Astro Compass

Above these types, the magnetic compasses can be of several types including:

• Prismatic compass or Lensatic compass
• Surveyor’s compass
• Marine compass or Card compass
• Liquid compass
• Thumb compass
• Orienteering compass or Baseplate compass
• Qibla compass
• Solid-state compasses

Magnetic Compass

This type of compass has a magnetized needle in line as well as having magnetic poles of the earth. This type of compass helps to determine the magnetic bearing of a line. In this case, the magnetic bearing can be determined in the Quadrantal Bearing System or Whole Bearing System. This magnetic compass has been classified into other several types which are:

Prismatic compass or Lensatic compass: This type of magnetic compass has been used for lining up with an object. In this type of compass, a magnifying lens is used for map reading. This is also used for plotting or military purposes.

This is the hand compass of the surveyor which consists of a triangular prism scale that is used for taking accurate observations. The bearings of lines have been calculated by this type of compass with respect to the magnetic needle.

Surveyor’s compass: This type of compass has been used by the surveyor for determining the horizon angles as well as estimating the magnetic bearing of a line of sight. The horizontal angle has been determined by using a pair of sights which has been located on the north-south axis of the surveyor’s compass.

Marine compass or Card compass: A needle is used in this type of compass, in which a compass card has been mounted in the fluid and also rotates on the basis of the orientations. This marine compass has been used in boats as the moving card has the ability to absorb the motion of the boat.

Liquid compass: In this type of compass, in which the compass card rests on a pivot inside a capsule which is filled with liquid. In this case, lamp oil, mineral oil, purified kerosene, white spirits, or ethyl alcohol have been used as liquid.

Thumb compass: This type of compass is the type of base plate compass which is fixed on the thumb and leaves one hand free. In orienteering, in which map reading and terrain association are required, a thumb compass can be used. The thumb compasses are quick-dampening and have higher visibility than other types of magnetic compasses.

Orienteering compass or Baseplate compass: This is also a liquid-filled compass which has been placed on a rectangular base that is made of transparent plastic. As a result, the map can be read easily. A magnifying lens has been used in this compass for map reading. Some of the baseplate compasses are the sort of lights for low light conditions as well as some baseplate compasses have been used as a ruler.

Qibla compass: This type of compass has been used by Muslims for identifying the direction of Mecca, as a result, they can determine the direction to face while they are praying. In Islam, the direction of praying is known as qibla which points towards Mecca city.

Solid-state compasses: This type of compass has been mainly used in electric devices. Two or three magnetic field sensors are present in the solid-state compasses in which the microprocessor helps to read data about the device’s orientations. Generally, solid-state compasses are used in mobile phones, tablets, or clocks.

GPS compass

Global Positioning System compass or GPS compass has been used in satellites in the geosynchronous orbit over the Earth which helps to show the exact direction and location of the bearer. The accurate position of the antennae on the Earth has been also determined by using this compass which helps to calculate the cardinal directions.

Gyro Compass

This type of compass is the form of a gyroscope which has been used on ships. A fast-spinning gyroscope wheel has been employed along with frictional forces which helps to influence the gravity and the rotation of the earth for finding the true north.

Astro Compass

This is the navigational tool which involves using the various astronomical bodies to determine the direction of the true north. In the polar region where gyrocompasses and magnetic compasses are unreliable, this type of compass can be used. The current time and geographical position have been used in the form of longitude and latitude by using this compass.