What is the tangential method of tacheometry?
The tangential method of tacheometry is being used when stadia hairs are not present in the diaphragm of the instrument or when the staff is too far to read. In this method, the staff sighted is fitted with two big targets (or vanes) spaced at a fixed vertical distances.
What is stadia system of tacheometry?
1. Stadia System of Tacheometry; In the stadia system, the horizontal distance to the staff Station from the instrument station and the elevation of the staff station concerning the line of sight of the instrument is obtained with only one observation from the instrument Station.
What are the three methods of tacheometry?
The various methods of the tacheometric survey may be classified as follows:
- The Stadia System. Fixed Hair Method. Movable Hair Method, or Subtense Method.
- The Tangential System.
- Measurements by means of Special Instruments.
What is stadia method in surveying?
: a surveying method for determination of distances and differences of elevation by means of a telescopic instrument having two horizontal lines through which the marks on a graduated rod are observed also : the instrument or rod.
What is the principle of stadia method?
The stadia method is based upon the principle of similar triangles. This means that, for a triangle with a given angle, the ratio of opposite side length to adjacent side length (tangent) is constant.
What is stadia intercept?
a method of surveying in which distances are read by noting the interval on a graduated rod intercepted by two parallel cross hairs (stadia hairs, or stadia wires ) mounted in the telescope of a surveying instrument, the rod being placed at one end of the distance to be measured and the surveying instrument at the …
What is the principle of a stadia method?
What are the types of stadia system?
The telescope used in stadia surveying are three kinds, The Simple external focusing telescope. The external focusing anal lactic telescope (porro’s telescope). The internal focusing telescope. The first type is known as stadia theodolite, while the second type is known as tacheometer.
What is stadia measurement?
Greek unit of measurement, the stade, the distance covered in the original Greek footraces (about 600 feet [180 metres]).
What is stadia used to measure?
Stadiametric rangefinding, or the stadia method, is a technique of measuring distances with a telescopic instrument. The term stadia comes from a Greek unit of length Stadion (equal to 600 Greek feet, pous) which was the typical length of a sports stadium of the time.
Which method of tacheometry is commonly used?
stadia Method
In stadia Method Fixed stadia method is commonly used. (i) Here in this system of tacheometry, the hairs are not at all required. (ii) This method can even be used when telescope is not provided with a diaphragm. (iii) The staff had two targets at a fixed distance (s) apart.
Which instrument is used for tacheometry survey?
tacheometer
The instrument for tacheometry is the tacheometer. By means of it the horizontal distance is determined by optical or electronic (electro-optical) distance measurement, and the horizontal angle is determined numerically or graphically.
What is the stadia system in tacheometric surveying?
Such methods are generally sluggish and often tiresome. Stadia System. Tangential system. In the stadia method, the horizontal gap from the instrument station to the staff station and the staff station height referring to the instrument’s line of sight is achieved with just one measurement from the Field device.
How is the tangential system used in tacheometry?
The Tangential System of Tacheometry: This method is used when the telescope is not fitted with a stadia diagram. In this method, the telescope is directed towards the staff to which the horizontal and vertical distances are to be measured and two vertical angles to two vanes or targets on the staff at a known distance (S) apart are taken.
How is line of sight measured in stadia method?
Tangential system. In the stadia method, the horizontal gap from the instrument station to the staff station and the staff station height referring to the instrument’s line of sight is achieved with just one measurement from the Field device. Movable hair method/Subtense Method.
How is the distance between stadia hairs measured?
In the stadia system of tacheometry there are two methods of surveying viz: (ii) Moveable hair method. In this method, the distance between the stadia hairs is fixed.