Plane table survey is one of the oldest and most traditional methods used in land surveying. This technique involves the use of a simple yet indispensable tool – the plane table. A plane table is a sturdy and versatile instrument that enables surveyors to accurately map and measure land. However, the use of a plane table alone is not sufficient. To carry out a successful plane table survey, it is crucial to have the right set of equipment and tools at hand. In this article, we will delve into the various equipments used in plane table survey and understand their uses in the field of land surveying.
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Equipments for Plane Table Surveying
Plane table surveying is a method of surveying in which a simple drawing board or plane table is used as the main instrument for measurement and mapping of an area. It is a practical and efficient method for conducting surveys in areas with rugged terrains, where other equipment like total stations or GPS may not be feasible. In this article, we will discuss the different types of equipment used for plane table surveying.
1. Plane Table: The most essential equipment for plane table surveying is a plane table, which is a drawing board mounted on a sturdy tripod. The table is usually made of wood or aluminum and has a smooth surface for drawing and placement of instruments. The tripod can be adjusted to different heights and is used to stabilize the table on the ground.
2. Alidade: An alidade is a telescope-like instrument that is mounted on top of the plane table. It is used to sight and measure the angles and directions in the field. The alidade is equipped with a vernier scale that allows precise angle readings. Some modern alidades also come with a built-in compass and spirit level for accurate measurements.
3. Spirit Level: A spirit level is a small bubble level attached to the alidade or the plane table itself. It is used to ensure that the table is perfectly horizontal, which is essential for accurate measurements. Some plane tables also come with a built-in spirit level for convenience.
4. Ranging Rod: Ranging rods are important instruments used for plane table surveying. They are used to measure the distance between the instrument and the point being surveyed. Ranging rods are usually made of wood or metal and are marked with a scale for measurement.
5. Plumb Bob: A plumb bob is a weight attached to a string or wire, which is used to determine the vertical direction. It is used in plane table surveying to ensure that the alidade is perfectly vertical when taking measurements.
6. Surveyor’s Chain: A surveyor’s chain is a measuring tape or rope marked with specific units of measurements, usually feet or meters. It is used to measure distances and is an essential equipment for plane table surveying.
7. Tripod Stand: A tripod stand is used to support and stabilize the plane table on the ground. They come in different sizes and materials, such as wood, aluminum, or plastic. The tripod stand should be sturdy enough to withstand the weight of the plane table and other equipment placed on it.
8. Marking Pins: Marking pins are used to mark survey points and drawing details on the plane table. They are usually made of steel or plastic and have pointed ends for insertion into the ground.
9. Drawing Sheets or Tracing Paper: The plane table surveying method involves drawing a map of the area being surveyed. Hence, drawing sheets or tracing paper is an essential equipment for this purpose. The sheets or paper should be large enough to accommodate the entire area being surveyed.
In conclusion, these are some of the essential equipments used in plane table surveying. The choice of these equipments depends on the terrain and the type of survey being conducted. These instruments are of utmost importance in ensuring accurate and efficient surveying results. It is crucial to have a complete set of well-maintained tools to carry out successful plane table surveys.
In conclusion, the equipment used in plane table survey plays a crucial role in accurately measuring and mapping land. From the basic plane table and alidade to the more advanced theodolite, all these tools have their specific uses and functions in the surveying process. The use of electronic equipment has greatly improved the accuracy and efficiency of plane table surveys, making it an essential tool for engineers, architects, and land surveyors. It is important to carefully select and maintain these instruments to ensure precise and reliable results. With the advancement of technology, we can expect further developments and improvements in plane table survey equipment, making it an indispensable tool in the field of land surveying.