Difference Between Plane Table Surveying and Compass Surveying | Plane table vs Compass Surveying |

Описание: Difference Between Plane Table Surveying and Compass Surveying
Plane table vs Compass Surveying

■ Plane Table Surveying

Plane table surveying is a graphical method of surveying in which fieldwork and plotting are done simultaneously. It is mainly used for small and medium-scale surveys where high precision is not required.


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Principle

The principle of plane table surveying is parallelism, meaning that all the lines drawn on the plan are parallel to the corresponding lines in the field. This allows for direct plotting of measurements without needing field notes.


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Equipment Used in Plane Table Surveying

1. Plane Table – A flat, smooth wooden board mounted on a tripod.


2. Alidade – A sighting device with a straight edge, used for sighting and drawing lines.


3. Tripod Stand – Provides support and stability for the plane table.


4. Plumbing Fork & Plumb Bob – Used to position the table exactly over a station.


5. Spirit Level – Ensures the table

■ Compass Surveying

Compass surveying is a type of surveying in which a magnetic compass is used to determine the direction of survey lines with respect to the magnetic meridian. It is mainly used for rough surveys where high accuracy is not required.


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Principle of Compass Surveying

Compass surveying works on the principle of magnetism. A freely suspended magnetic needle aligns itself with the Earth's magnetic field, pointing towards the magnetic north. This allows the surveyor to measure the bearing (angle) of survey lines from the magnetic meridian.


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Instruments Used in Compass Surveying

1. Prismatic Compass – A magnetic compass with a sighting device and prism for reading bearings.


2. Surveyor’s Compass – A compass that measures bearings with respect to the true north.


3. Tripod Stand – Provides stability for the compass.


4. Chain or Tape – Used for measuring distances.

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