8.35 pixel
2-dimensional picture element that is the smallest nondivisible element of a digital image. In image processing, the smallest element of a digital image that can be assigned a grey
level.
NOTE This term originated as a contraction for “picture element”.
8.36 photogrammetry
use of aerial photographs to produce planimetric and topographic maps of the earths surface and of features of the built environment
NOTE Effective photogrammetry makes use of ground control by which aerial photographs are
carefully compared and registered to the locations and characteristics of features identified in ground-level surveys.
8.37 position
spatial reference of a point or an object
8.38 query language
computer language in which server requests are defined
NOTE Query languages are often server-specific.
8.39 server request
set of instructions passed to the server to initiate desired operations, such as to retrieve needed information
8.40 stereoscopic images
two images of a single target allowing three-dimensional viewing of a target.
NOTE 1 The two images or photographs must have sufficient overlap of detail to make possible
stereoscopic examination of an object or an area common to both images. NOTE 2
The two or more images of the same object or target must be taken from different imaging positions in space, and thus different object viewing directions. These multiple images can be used to
determine object position or dimensions in three-dimensions. Two stereoscopic images are often taken from different points along one flight path, but there are also stereoscopic images from different flight
paths.
8.41 transformation
change of coordinates from one coordinate reference system to another coordinate reference system based on a different datum through a one-to-one relationship
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NOTE A transformation uses parameter values which may have to be derived empirically by a set of
points common to both coordinate reference systems. See coordinate conversion and coordinate transformation.
8.42 unit
defined quantity in which dimensioned parameters are expressed
NOTE In this document, the subtypes of units are length units, angular units, time units, and pixel
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