What is the relationship between surveying and mapping scale and ground sampling point spacing?

Ground sampling interval is the distance between adjacent pixel centers, which is limited by spatial resolution.

The image points in the photo are distributed continuously, but it is impossible to digitize all the continuous image points in the process of image digitization, and only the gray value of one point can be read every once in a while. This process is called sampling. The time interval or space interval between two adjacent samples is the sampling interval. 1: 5000, 1: 10000, about 1: 20000, 0.4 to 0.8 1, 1: 10000.

The experimental data is very mature. There is no direct requirement for image resolution in aerial photogrammetry, but it can be inferred from the requirement for objective resolution of camera and photographic scale. The resolution of camera lens in aerial photography represents the minimum line width that can be resolved in the image after aerial photography. The resolution of film and paper is not considered here. In the aerial photography standard GB/T15661-1995, it is stipulated that the lens resolution in the effective use area of aerial photography is "not less than 25 line pairs per millimeter". According to the objective resolution and photographic scale, the corresponding ground resolution d on aerial photographic images can be estimated, that is, d = m/r, where m is the denominator of photographic scale and r is the lens resolution. According to the "selection of aerial photography scale" in the aerial photography specification and the above formula.