The purpose and process of photogrammetry

The definition of traditional photogrammetry: it is a subject that obtains the shape, size, position, characteristics and their relationship of the object by processing the photos obtained by optical cameras.

Photogrammetry is a branch of surveying and mapping. Its main task is mapping topographic maps of various scales, establishing digital ground models and providing basic data for various geographic information systems and land information systems. The two major problems to be solved in photogrammetry are geometric positioning and image interpretation. Geometric positioning is to determine the size, shape and spatial position of the object being photographed. The basic principle of geometric positioning comes from the forward intersection method of measurement. According to two known photographic stations and two known photographic direction lines, they intersect with the three-dimensional coordinates of undetermined ground points that constitute these two photographic rays. Image interpretation is to determine the attributes of ground objects corresponding to images.

The process is very simple, that is, photography+measurement in the photo.