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Construction is one of the largest industries in the world. Surveying plays an extremely important role in any construction project. Construction surveying can take many forms. It is used to establish the location and alignment of highways, bridges, buildings, pipelines, and other man-made objects. After large-scale projects are completed, an "as-built" survey is usually performed to locate any modifications that were made to the plans during construction.
 
In the case of buildings, an arbitrary system of grids is often established so as to correspond to the rows of columns and the major load-bearing walls of the building. The grids may be identified alphabetically in one direction, and numerically in the other direction (as in a road map). The grids are usually but not necessarily perpendicular, and are often but not necessarily evenly spaced. Floors and basement levels are also numbered. Structures, equipment or architectural details may be located in reference to the floor and the nearest intersection of the arbitrary axes.
 
Surveying equipment, such as levels and theodolites, are used for accurate measurement of angular deviation, horizontal, vertical and slope distances. The builder measures neither horizontal nor vertical angles. It simply combines a spirit level and telescope to allow the user to visually establish a line of sight along a level plane. When used together with a graduated staff it can be used to transfer elevations from one location to another.