What is photogrammetry? What are the advantages?

Compared with traditional measurement, photogrammetry has the advantages of high efficiency, fast update and labor saving. * * * Sex is sometimes the method of intersection. The difference is that photogrammetry needs photo interpretation, and the accuracy is slightly poor.

1, the tested object is the tested object:

Mainly refers to geometric quantities, including length, area, shape, elevation, angle, surface roughness and form and position error. Because geometric quantities have various types and shapes, it is necessary to study and be familiar with their characteristics, definitions and standards of measured parameters when measuring.

2. Measurement unit:

China's the State Council reiterated in Article 3 of "Regulations on Metrology Management in People's Republic of China (PRC) (Trial)" issued on May 27th 1977: "China's basic measurement system is metric, and the international system of units is gradually adopted."

1984 On February 27th, the legal units of measurement in People's Republic of China (PRC) were officially announced, and the metric system was determined as the basic measurement system in China. In length measurement, the unit is meter (m), and other commonly used units are millimeter (mm) and micron (micron). In angle measurement, the units are degrees, minutes and seconds.

3. Measurement method:

Refers to a logical sequence of operations described by classes used in measurement. The measurement of geometric quantity is based on the characteristics of measured parameters, such as tolerance value, size, weight, material, quantity and so on. And analyze the relationship between this parameter and other parameters, and finally determine how to measure this parameter.

4. Measurement accuracy:

Refers to the degree of consistency between the measured results and the true values. Because any measurement process will inevitably produce measurement errors, large errors indicate that the measurement results are far from the real values and the accuracy is low. Therefore, accuracy and error are two relative concepts. Due to the measurement error, any measurement result is expressed as an approximation.