# Scale Definitions for Land Surveyors

scale- 1 An indication of the relationship between the distances on a map, chart, or plan and the corresponding actual distances, usually in the form of a direct statement (as one inch to one mile), as a fraction (I: 250.000), a graphic measure such as a bar or line subdivided at selected intervals. 2 A mathematical instrument consisting of a strip (as of wood, plastic, or metal) with one or more sets of spaces graduated and numbered on its surface and used especially for measuring or laying off distances or dimensions (as in drawing or plotting); engineer’s scale. See also map scale; photo scale.

scale factor—A multiplier for reducing a distance obtained from a map by computation or scaling to the actual distance on the datum of the map. In the state plane coordinate system, scale factors are applied to geodetic lengths to obtain grid lengths, or to grid lengths to obtain geodetic lengths. Both are lengths on a sea-level datum, but the grid lengths are affected by the distortion of the map projection.

scale point—A point on a photograph at which the scale is known.

scale-point method—A method of determining the amount of tilt in an aerial photograph by using the scale at three points (scale points) in he photograph for which the elevations of the corresponding ground-points are known.

scaling—1 The process of determining the scale of something, such .us of a photograph or map. 2 A step, in the absolute orientation of a stereoscopic model, in which the scale of the model is adjusted. Alas called “scaling the model.” 3 The process of changing the scale in a stereoscopic model to bring the size of the model in agreement with a plot of horizontal control.

Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

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