Research on 3D geological modeling method based on section thinning-densification and close-range photogrammetry

When 3D modeling of the geological body is carried out based on the section, problems such as unable to close the structural plane, slow rendering speed of the model and uneven and long and narrow section triangle network will occur due to the situation of super near point or too dense fold point. To solve the appealing problem, this paper proposes a section thinning-densification method based on the Douglas Peucker algorithm and equidistance algorithm. When processing the original section data, the Douglas Peucker algorithm is used for thinning, and then the equal distance is used for density increase. In this way, the section obtained by thinning-densification method solves the problem of uneven break points on the original section line and does not affect the shape of the section line, effectively solving the problem caused by too dense or too sparse break points on the section line in 3D geological modeling Series of modeling problems. In this paper, through the research on the modeling method of the above ground structure, the application demonstration of the above-ground and underground integrated three-dimensional model construction in Chengdu International Biological city is carried out, which verifies that the above-ground and underground integrated three-dimensional model construction technology is feasible and applicable and worthy of promotion.