What are the applications of UAV aerial photogrammetry in terrain mapping?

Jun 27, 2023

In order to adapt to the current form of national basic surveying and mapping work, UAV aerial photogrammetry technology has been widely valued by people. UAV aerial photogrammetry makes up for the shortcomings of traditional surveying and mapping technology, and plays a huge role in the current stage of topographic mapping.

1. Control measurement of photos

The control and measurement of photos is one of the most important technologies in UAV aerial photography technology. The so-called photo control measurement is to integrate the data taken by the drone with the navigation and positioning information in the GPS system, convert the data obtained by the aerial photography of the drone and the measurement data on the ground, and obtain the real topography of the area. feature. Especially for some terrains or areas that need special attention, the data can be directly transmitted, recorded and saved through aerial photography of drones. Among them, it is necessary to pay attention to the setting of the control points other than the photo control points, which should be set in more obvious places, so as to obtain more ideal data.

2. Aerial triangulation in aerial photogrammetry

Aerial triangulation is also a relatively common technique in UAV aerial photogrammetry. UAVs use aerial digital camera equipment to perform aerial triangulation technology, which can measure the specific position of terrain. One of the advantages of aerial triangulation is that it can automatically calculate with the help of pre-edited system programs, so as to obtain the corresponding terrain position information. The cumbersome steps of manually setting aerial digital camera equipment are eliminated. With such aerial triangulation techniques, relative orientation can be achieved smoothly. After this step is completed, use the system to connect the survey flight belt with the survey model, and then use aerial triangulation for data calculation, and use the obtained connection point data and image control points as debugging information to draw a more accurate terrain picture.

3.Stereoscopic collection and editing of measurement data

Obtaining data through UAV aerial photogrammetry can use the three-dimensional information in the industry to collect, edit and manage the terrain data information of the measured area. In order to ensure the accuracy and reliability of the three-dimensional acquisition and editing of measurement data, important information such as contour lines and waterlines can be edited manually, and other general information can be edited three-dimensionally by computer. This link needs to pay attention to the precise control of object line nodes and terrain structure data, etc., to ensure the accuracy of the data obtained by drone aerial photography, otherwise it will affect the accuracy of stereoscopic acquisition and editing. If the information surveying and mapping of the house structure is carried out, the outline of the outer edge of the house should be processed first, and the edge or outline of the eaves should be corrected to ensure the accuracy of the data measurement; if there are areas that cannot be measured, they should be carefully marked to ensure the accuracy of the topographic measurement and wholeness.

4.Field supplementary measurement of blind spots in aerial measurement

No matter how advanced the surveying and mapping tools are, they cannot measure all terrain areas, and the blind spots in the survey need to be measured by manual supplementary surveys to measure terrain structures and even hidden areas. In the process of field supplementary measurement, it is necessary to pay attention to comparative analysis, and compare the actual measurement data with the results of drone aerial photography, so as to mutually verify the accuracy of the surveying and mapping data. If there is a large deviation, analyze the cause of the error and correct it in time to ensure the accuracy of the surveying and mapping results. The interference of human factors and the common measurement accidents in traditional surveys should be avoided as much as possible when conducting aerial surveys by UAVs, so as to ensure the accuracy and breadth of surveying and mapping data.