|
In terms of the shortcomings of traditional vertical photogrammetry in urban modeling, such as tilt deformation and occlusion of near ground objects, a typical area in Qiaocheng District of Bozhou City, China is selected as the study area. DOM, TDOM, vertical traditional 3D model, vertical true 3D model as well as realistic 3D model based on low-altitude vertical photogrammetry and tilt photogrammetry data of the study area are constructed, comparing the modeling accuracy of different models, and the accuracy of DLG production and drawing details of different 3D models as well as the accuracy of extraction of building area are studied. The spatial data of the check points in the study area is measured to test the feasibility of constructing large scale (1:500) of digital line graphs via different 3D models. The results show that: ①the mean square error in plane of DOM, TDOM, vertical traditional 3D model, vertical true 3D model and realistic 3D model is respectively ±0.368cm, ±0.78cm, ±4.67cm, ±2.63cm, ±0.80cm, the mean square error in elevation of which is respectively±8.16cm, ±0.89cm, ±8.17cm, ±0.84cm, ±0.93cm. ②refer to the "Code for Aerial Triangulation of Digital Aerial Photogrammetry", according to the realistic 3D model, the minimum accuracy in plane is 4.79cm, the maximum accuracy in plane is 0.15cm, and the mean square error in plane is ±0.80cm; the minimum accuracy in elevation is -5.72cm, and the maximum accuracy in elevation is 0.26cm, the mean square error in elevation is ±0.93cm, it can be seen that the realistic 3D model meets the standard of large scale (1:500) topographic map drawing. ③measure 150 evenly distributed checkpoints in the study area through GPS RTK, and compare them with the elevation check points extracted from the DLGs produced by the vertical traditional 3D model, the vertical true 3D model as well as the realistic 3D model, the maximum error in elevation of the comparison result is 54.39cm, 17.41cm as well as 14.89cm respectively, and the mean square error in elevation is ±2.27cm, ±0.35cm as well as 0.33cm respectively, referring to "1:500 1:1000 1:2000 Topographic Map Aerial Photogrammetry Industry Specifications", it can be seen that the digital line graphs constructed by vertical true 3D model and realistic 3D model meet the accuracy of drawing large scale (1:500) digital line graph, specially, the digital line graph constructed by the realistic 3D model is more complete and more accurate.
|
