What is photogrammetry?

Photogrammetry has the advantages of high efficiency and quick updating to save labor compared to traditional surveying. ***The difference between photogrammetry and traditional surveying is that photogrammetry requires photo interpretation and is slightly less accurate. The difference is that photogrammetry requires photo interpretation and is slightly less accurate.

1, the measurement of the object that is the object of measurement:

Mainly refers to geometric quantities, including length, area, shape, elevation, angle, surface roughness, and form and position errors. Since geometric quantities are characterized by a wide variety of types and shapes, their characteristics, the definition of the parameters to be measured, as well as standards must be studied and familiar with in order to carry out the measurement.

2, unit of measurement:

China's State Council on May 27, 1977 issued the "Chinese People's **** and the State Measurement Management Regulations (for trial implementation)," reiterated in the provisions of the third article: "China's basic measurement system is the metric system (i.e., metric system), and the gradual adoption of the International System of Units."

On February 27, 1984, the official announcement of the Chinese People's *** and the State legal units of measurement, to determine the metric system as China's basic measurement system. In length measurement in units of meters (m), other common units are millimeters (mm) and microns (μm). In angular measurement in degrees, minutes, seconds as the unit.

3, measurement method:

refers to the measurement used in the class described in a set of logical sequence of operations. For the measurement of geometric quantities, it is based on the characteristics of the measured parameters, such as tolerance values, size, weight, material, quantity, etc., and analyze and study the relationship between the parameter and other parameters, and finally determine how to measure the parameter of the operation.

4, the accuracy of the measurement:

The degree of agreement between the measurement results and the true value. As any measurement process will always inevitably occur in the measurement error, error shows that the measurement results far from the true value, low accuracy. Therefore, accuracy and error are two relative concepts. Due to the existence of measurement error, any measurement results are expressed as an approximation.