What are the three stages of the development of photogrammetry?

The development of photogrammetry has gone through three stages: analog photogrammetry, analytical photogrammetry and digital photogrammetry.

Photogrammetry is an information science that studies the acquisition, processing, extraction and expression of results through images. Traditional photogrammetry is a science and technology to study and determine the shape, size, nature and relationship of the photographed object by using the images taken by optical cameras.

Including the following contents: acquiring the image of the studied object, the theory, method, equipment and technology of single and multiple photo processing, and how to express the measurement results with graphics, images or numbers.

The main task of photogrammetry is to make topographic maps of various scales and establish topographic databases to provide basic data for various geographic information systems and land information systems. Therefore, the development of photogrammetry in theory, methods, instruments and equipment is influenced by topographic survey, map drawing, digital mapping, survey database and geographic information system.

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The main feature of photogrammetry is to measure and interpret photos without touching the object itself, so it is rarely limited by natural and geographical conditions. An image is a true reflection of an objective object or target, which is rich in information and realism. People can get a lot of geometric information and physical information of the studied object from it.

Photogrammetry can be widely used in all aspects. As long as the object can be photographed as an image, some problems can be solved by photogrammetry methods and techniques. The object can be solid, liquid or gas; It can also be static or dynamic; It can be very small or very big.

Because of these flexibility, photogrammetry can be used not only for topographic mapping, but also for industry, architecture, biology, medicine and archaeology. Therefore, photogrammetry can be divided into topographic photogrammetry and non-topographic photogrammetry.