3D point clouds vs. measurements from photographs
3D laser scanning is a non-contact, non-destructive technology that digitally captures spatial data on the physical environment using a line of laser light. 3D laser scanners create “point clouds” of data from the surface of an object.
Photogrammetry
Photogrammetry is the science of making measurements from photographs. The input to photogrammetry is photographs, and the output is typically a map, a drawing, a measurement, or a 3D model of some real-world object or scene. Many of the maps we use today are created with photogrammetry and photographs taken from aircraft. Photogrammetry can be classified several ways such as aerial or terrestrial.