The heading overlap of traditional aerial survey is generally set to

General provisions: courses overlap by 60%, at least 53%; The horizontal overlap is 30%, at least not less than 15%.

Course overlap refers to photo overlap, which refers to the overlap of the same image in adjacent photos. Among them, the overlapping part of two adjacent photos on the same route is called heading overlap. Route overlap, also known as "vertical overlap", means that in aerial photography, adjacent photos along the same route have the same ground image part. In aerial survey, the photos composed of adjacent photos in the same flight band overlap. Also known as "vertical overlap".

The ratio of the length of the overlapping part to the side length of the photo is called title overlap, which is expressed as a percentage. According to the needs of aerial photogrammetry, the course overlap is generally stipulated as 60%. On aerial cameras, special equipment is usually installed to automatically adjust the exposure interval to achieve the specified heading overlap. Course overlap is also called "vertical overlap".

In aerial photography, because adjacent photos are taken from different positions in the air, the overlapping parts are on the same ground, but the images are not exactly the same. Its function is: the aerial photos of traffic remote sensing belong to central projection, and with the change of projection distance, the inclination of projection area and the ups and downs of terrain, the error of projection distance will occur.

In order to ensure the interpretation accuracy of aerial photographs and meet the needs of dynamic traffic analysis, we should make use of the part of aerial photographs that is close to vertical projection as much as possible, which requires aerial photographs of the same route to keep some directions overlapping. The content of aerial photography is different, and the course overlap is also different.

Photo overlap

Photo overlap is a prerequisite for photogrammetry. In photogrammetry, the part of adjacent photos that contains images of the same area. The amount of overlap is expressed as a percentage of the total photo area, which is called overlap. Stereoscopic observation and model connection need enough photo overlap.

In aerial photogrammetry, the overlap between photos along the same route is called heading overlap or longitudinal overlap; The photo overlap between adjacent routes is called lateral overlap or lateral overlap. Course overlap and lateral overlap are necessary conditions for stereo observation, stereo measurement and photo connection.