基于Coons曲面与约束三角网的区域地质调查三维建模方法

目前基于野外地质调查数据自动、快速地建立区域三维地质体模型是中国全面开展三维数字地质填图的迫切需求。本文基于产状、地质界线与路线剖面等野外区域地质调查要素,提出了一种二维平面地质图及路线剖面图向三维地质体模型的快速转换方法。该方法针对无剖面约束及含剖面约束2种情形,通过地质界线区域分割、多段线仿射变换等空间几何变换处理,推估出剖面线约束的地下地质界线,基于Coons曲面构建出地质体的侧面模型;然后,通过约束三角网算法构建地质体的顶、底面模型,最终建立拓扑一致的区域地质体三维模型。基于此方法,对中国1:2.5万区域地质调查试点区域进行了区域三维地质建模实践,实现了火山口、地层、岩体、断层等典型地质构造的快速三维重建。

3D Regional Geological Modeling Based on Coons Surfaces and CD-TIN

Automatic and efficient regional three-dimensional (3D) geological modeling based on the field geological survey data is the key issue of the nationwide 3D geological mapping nowadays. Based on the fundamental geological survey elements such as the attitudes, boundaries and sections, a method for transforming the two-dimensional (2D) geological maps and route section maps into the 3D geological models was proposed in this paper. The geological bodies that are both constrained and non-constrained by route sections were taken into consideration in this method. For the geological bodies that are constrained by sections, through the spatial geometrical processing, such as boundary regional division and polyline affine transformation, the underground boundary could be estimated using the surficial boundary constrained by the section lines. Then, based on the Coons surface, the side surfaces of the geological body were constructed by filling the areas between the top and bottom boundaries and the section lines. Afterwards, the top and bottom surfaces of the geological body were constructed by the constrained Delaunay triangulation network and the topologically consistent regional geological model was finally constructed. Based on this workflow, a 3D geological modeling practice was carried out in the domestic 1:25 000 regional geological survey experiment area. In the experiment, some typical and complex geological structures, including the volcanic edifice, stratum, rock and faults were efficiently reconstructed.