How do you use a plane table?

How do you use a plane table?

The table should be approximately leveled by tripod legs and judging by the eye. Then the operation of centering is carried out by means of U-frame and plumb bob. The plane table is exactly placed over the ground station by U-frame and plumb bob.

What is the function of plane table?

A plane table (plain table prior to 1830) is a device used in surveying and related disciplines to provide a solid and level surface on which to make field drawings, charts and maps. The early use of the name plain table reflected its simplicity and plainness rather than its flatness.

What is the principle of plane table?

Plane table surveying is based on the principle that lines drawn during plotting always lie parallel to the corresponding lines actually present on the ground. For example, let us consider four ground stations A, B, C and D which on joining provides a rectangle ABCD.

Which instrument is used for plane table?

In a plane table surveying a table top, similar to drawing board fitted onto a tripod is the main instrument. A drawing sheet is fixed on to the table top, the observations are made to the objects, distances are scaled down and the objects are plotted in the field itself.

What are the types of Alidade?

Two types of alidade are used in plane table surveying, they are plain alidade and telescopic alidade.

What is the function of Alidade?

An alidade (/ˈæ. lɪ. deɪd/) (archaic forms include alhidade, alhidad, alidad) or a turning board is a device that allows one to sight a distant object and use the line of sight to perform a task.

What is the function of U fork?

U fork or plumbing fork with plumb bob- The U fork is a metal strip bend in the shape of U having equal arm length. The top arm is pointed and bottom arm carries a hook for suspending a plumb bob.

What is alidade table?

Definitions of alidade. surveying instrument used with a plane table for drawing lines of sight on a distant object and for measuring angles. synonyms: alidad.

What is the use of telescopic alidade?

The telescopic alidade is used when it is required to take inclined sights. It essentially consists of a small telescope with a level tube and graduated arc mounted on horizontal axis. It gives higher accuracy and more range of sights.

What is the use of dumpy level?

A dumpy level (also known as a Builder’s Level) is an optical instrument used to establish or check points in the same horizontal plane.

What is meant by Tacheometer?

A tachymeter or tacheometer is a type of theodolite used for rapid measurements and determines, electronically or electro-optically, the distance to target. The principles of action are similar to those of rangefinders.

Which process involves more Labour work?

Explanation: When compared to the three point problem, the solution obtained from two point problem involves more labour work as speed is the first priority. Explanation: Lehman’s process, also known as trial and error process, involves a lot of trial and error, which makes it a tedious process.

How do you solve a two-point problem?

A two-point problem is one of the methods of resection….Two-point Problem

1. While choosing point Q the triangles formed APQ and BPQ should be well-conditioned.
2. Point Q is roughly oriented, and A and B are plotted in it.
3. Now orient the plane table back sighting to Q produces the ray from A to intersect which is named p.

What is the another name of Bessel’s method in surveying?

Plane tabling is a graphical method of surveying in which the field observations and plotting proceed simultaneously. It helps in preparing a manuscript map in the field while the topographer sees the ground. It eliminates intermediate steps of recording and transcribing field notes.

How many Lehman’s rules are there in survey?

The trial and error method of three point problem, also known as Lehman’s method minimises the triangle of error to a point iteratively. The iterative operation consist of drawing of resectors from known points through their plotted position and the adjustment of orientation of the plane table.

What is lehmans rule?

@ : Home > Civil Engineering > Surveying. According to Lehman’s rule of plane tabling. [A]. the distance to the point sought from each of the three rays is proportional to the distance of the three known points from the instrument station. [B].

What is Bowditch rule in surveying?

4. ( 1)Bowditch’s Rule: The Bowditch’s rule, also termed as the compass rule, is mostly used to balance traverse when linear and angular measurements are equally precise. By this rule, the total error in latitude or departure is distributed in proportion to the lengths of the traverse legs.