What is Photogrammetry?
By definition given by the American Society for Photogrammetry and Remote Sensing (ASPRS), in the Mapping Sciences,

Photogrammetry is the art, science, and technology of obtaining reliable information about physical objects and the environment through the processes of recording, measuring, and interpreting photographic images and patterns of electromagnetic radiant energy and other phenomena.

From the Manual of Photogrammetry, Fourth Edition, published in 1980 by the ASPRS.  It should be noted that the term art is applied as meaning skill which is obtained through experience.

An older definition, from the Third Edition of the Manual of Photogrammetry, is somewhat simpler in statement and that definition of photogrammetry is,  the science or art of obtaining reliable measurements by means of photographs.

Photogrammetry can also be thought of as the sciences of geometry, mathematics and physics that use the image of a 3D scene on a 2D piece of paper to reconstract a reliable and accurate model of the original 3D scene.  With this in mind it is easier to understand the current expanded definition, which, includes the science of electronics by using video and other synthetic means of reproducing 2D images of 3D scenes.  And, these images are also used to reconstruct reliable and accurate models of the captured 3D scenes.

The collections of photographs (and video) in your case files are the best data base that you can have, and the 2D and 3D drawings reconstructed from them prove it. Photography has been used to accurately to determine the locations of marks and objects at a scene long after the items and the scene are no longer available for measurements.
 

Email: James R. Williamson, PhD, PE. Copyright © 1999-2005 - James R. Williamson, PhD, PE.