nadir point


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nadir point

[′nā·dər ‚pȯint]
(optics)

nadir point

nadir pointclick for a larger image
i. The same as nadir
ii. As it relates to aerial photogrammetry, it is the point where a plumb line dropped from the front nodal point pierces the photograph. This point is vertically beneath the exposure station. In the illustration, it is point N. Also called a photo nadir and a photo plumb point.