Displacement Definitions for Land Surveyors
displacement, height—Displacement of images radially inward or outward from the photograph nadir, according as the ground objects are, respectively, below or above the elevation of the ground nadir.
displacement, relief— Displacement of images radially inward or outward from the nadir point of the photograph. Relief displacement of images is caused by differences in elevation of the corresponding ground objects whether above or below, respectively, the elevation of the ground nadir.
displacement, tilt— Displacement of images on a tiled photograph radial from its isocenter. Tilt displacement is outward or inward with respect to the isocenter, according to whether the images are on the low or high side of the isometric parallel (the low side is the closest to the earth, or the object plane).
Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.
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