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The interval between stadia marks in most surveying instruments is 10 mrad and gives a stadia interval factor of 100. The distance between the instrument and a stadia rod can be determined simply by multiplying the measurement between the stadia hairs (known as the stadia interval) by 100. The instrument must be level for this method to work ...
This ratio is known as the stadia constant or stadia interval factor. Thus the formula for distance is D = kS. where D is distance from the telescope to the rod; k is the stadia constant; S is the difference between the rod readings at the two stadia marks; For example, a typical stadia mark pair are set so that the ratio is 100.
A level staff, also called levelling rod, is a graduated wooden or aluminium rod, used with a levelling instrument to determine the difference in height between points or heights of points above a vertical datum.
The other standard method of levelling in construction and surveying is called trigonometric levelling, which is preferred when levelling "out" to a number of points from one stationary point. This is done by using a total station , or any other instrument to read the vertical, or zenith angle to the rod, and the change in elevation is ...
This reduces the need to set the instrument base truly level, as with a dumpy level. Self-levelling instruments are the preferred instrument on building sites, construction, and during surveying due to ease of use and rapid setup time. A digital electronic level is also set level on a tripod and reads a bar-coded staff using electronic laser ...
The method of surveying a field or other parcel of land with Gunter's chain is to first determine corners and other significant locations, and then to measure the distance between them, taking two points at a time. The surveyor is assisted by a chainman.
Wild brand subtense bar. Another device used in tacheometry to measure distance between the measuring station and a desired point is the subtense bar. [2] This is a rigid rod, usually of a material insensitive to change in temperature such as invar, of fixed length (typically 2 metres (6.6 ft)).
Deformation monitoring is primarily associated with the field of applied surveying but may also be relevant to civil engineering, mechanical engineering, construction, and geology. The measurement devices utilized for deformation monitoring depend on the application, the chosen method, and the preferred measurement interval.