Photogrammetry, the practice of obtaining accurate measurements from a photograph, is a technique nearly as mature as photography. One of the most rudimentary forms, perspective grid photogrammetry, utilizes an object of known dimensions within the photograph to determine the spatial relationships of evidence in the photograph. By measuring the location of two points, each piece of evidence captured within a photograph may be extrapolated. This enables on scene crime scene investigation work to be completed in a fraction of the time typically required using baseline or triangulation measurements. Spending less time measuring can be advantageous for those crime scenes located in war zones, in situations in which bad weather will disrupt the crime scene, or whenever the time at the crime scene must be minimized.
Off the Grid: Perspective Grid Photogrammetry in Crime Scene Reconstruction
Flanagan, J.; Robinson, E. Off the Grid: Perspective Grid Photogrammetry in Crime Scene Reconstruction. J. Assoc. Crime Scene Recon., 2011, 17(4), 57-61.