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Dimensional control survey: This is a type of survey conducted in or on a non-level surface. Common in the oil and gas industry to replace old or damaged pipes on a like-for-like basis, the advantage of dimensional control survey is that the instrument used to conduct the survey does not need to be level.
While it is possible to use only two known control points in a resection (free stationing), it is recommended to use three control points. There is no redundancy for orientation, using two points only. [7] When performing a resection (free-stationing) on more than 4 points, diminishing returns are achieved in the returned results. [5] [6]
Traverse networks involve placing survey stations along a line or path of travel, and then using the previously surveyed points as a base for observing the next point. Connected survey lines form the framework and the directions and lengths of the survey lines are measured with an angle measuring instrument and tape or chain. [2]
Classically, a control is divided into horizontal (X-Y) and vertical (Z) controls (components of the control), however with the advent of satellite navigation systems, GPS in particular, this division is becoming obsolete. In the U.S., there is a national control network called the National Spatial Reference System (NSRS). [2]
The survey party installs control stations at regular intervals. These are small steel plugs installed in pairs in holes drilled into walls or the back. For wall stations, two plugs are installed in opposite walls, forming a line perpendicular to the drift. For back stations, two plugs are installed in the back, forming a line parallel to the ...
Astronomical survey, imaging or mapping regions of the sky; Field survey, or field research Archaeological field survey, collection of information by archaeologists prior to excavation; Geological survey, investigation of the subsurface of the ground to create a geological map or model; Site survey, inspection of an area where work is proposed
Survey methodology is "the study of survey methods". [1] As a field of applied statistics concentrating on human-research surveys, survey methodology studies the sampling of individual units from a population and associated techniques of survey data collection, such as questionnaire construction and methods for improving the number and accuracy of responses to surveys.
A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable (i.e. confounding variables). [1] This increases the reliability of the results, often through a comparison between control measurements and the other measurements. Scientific controls are a part of the ...