control point

Aerial Photogrammetry.

a point located on the ground by precise surveying that when identified on aerial photographs provides the control necessary for producing a photomap.

[1925-30]

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control point,

1. a point or feature used for purposes of reference or orientation, as a landmark in navigation: »

The geodesist…establishes what are called geodetic control points, locations he has pinned down…as a guide for plotting all other locations and computing all distances (Life).

2. a position or station used for control and regulation of traffic: »

Studies by Stanford's Engineering Division…suggest that pictures of trains moving at 60 miles an hour can be flashed to the appropriate control point in a matter of seconds (New Scientist).