Plane Table Surveying

 Plane Table Surveying is a traditional surveying method that involves the use of a flat drawing board (known as a plane table) and a specialized alidade to take precise measurements and make accurate drawings of the terrain being surveyed. This method of surveying is often used in areas where a detailed survey of a small area is required, or where access to the area being surveyed is limited.

In Plane Table Surveying, the plane table is placed on a tripod, and the surveyor uses the alidade to sight various points on the terrain. The alidade has a sighting mechanism, typically a telescope, which allows the surveyor to take precise readings of the angles between different points on the terrain. These readings are then transferred to the plane table, where they are used to create a scaled drawing of the terrain being surveyed.

One advantage of Plane Table Surveying is that it allows for a more detailed survey of a smaller area than other methods, such as Total Station Surveying or GPS Surveying. It is also a relatively simple and low-tech method of surveying, which makes it ideal for use in remote areas or in situations where access to more sophisticated equipment is limited.

Overall, Plane Table Surveying is a valuable and still-used method of surveying, especially for specific applications where its unique advantages and limitations make it the best choice.

What are the Instruments use in Plane Table Surveying 

The main instruments used in Plane Table Surveying are:

• Plane Table: A flat drawing board used to make sketches and drawings of the terrain being surveyed.
• Alidade: A sighting device used to measure angles between points on the terrain. The alidade typically consists of a sighting mechanism, such as a telescope, and a protractor for measuring angles.
• Tripod: A stable support used to hold the plane table in a fixed position while surveying.
• Spirit Level: A device used to ensure that the plane table is level, which is critical for accurate readings.
• Scale: A measuring tool used to determine the correct scale of the drawings made on the plane table.
• Pencils and drawing materials: Used to make sketches and drawings on the plane table.
• Ruler or scale bar: A measuring tool used to determine distances on the plane table.

In addition to these core instruments, Plane Table Surveying may also require other tools, such as a plumb bob, a level staff, or a sighting rod, depending on the specific surveying task being performed.