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A system of aerial photography in which one vertical and two oblique photographs are simultaneously taken for use in topographic mapping.

[tri- + Metrogon, trademark for a kind of camera lens.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


a. a method of aerial photography for rapid topographic mapping, in which one vertical and two oblique photographs are taken simultaneously
b. (as modifier): trimetrogon photography.
[from tri- + metro-, from Greek metron measure + -gon]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
In the 1946-47 southern summer, Martin Mariner seaplanes and other aircraft operating from aircraft carriers, took some 65,000 aerial photographs with trimetrogon cameras, covering nearly half of the Antarctic coastline (Rose & Conger 1980, 249-250).
Photogrammetric rectification of oblique Trimetrogon imagery.
Another eight maps illustrate the expedition routes, territorial claims, and Operation Highjump's trimetrogon photogrammetric mapping of one and a half million square miles of Antarctica.
This oblique (trimetrogon) coverage was completed by the Royal Canadian Air Force in the early 1950s, and the coverage of vertical photography was completed in the late 1950s.