一种基于GTP的地下真3D集成表达的实体模型

从建模对象、组成元素和拓扑描述三个方面对广义三棱柱(GTP)模型进行了修正和扩展。基于修正与扩展后的GTP模型,从地学、几何、拓扑三个层面对地下实体进行了提炼,抽象出8种空间构模几何元素,并将地下实体划分为点、线、面和体4类,体实体又进一步划分为简单体、复合体和复杂体,进而提出了一种基于GTP的地下真3D集成表达的实体模型(GTP-based entity model,GTP-EM);采用面向对象的方法,通过构模元素之间拓扑关系的定义实现了地下实体的拓扑描述,并应用实例验证了GTP-EM的可行性。

A GTP-based Entity Model for Underground Real 3D Integral Representation

Based on the amended and extended GTP model,the underground entity is extracted in levels of geosciences,geometry and topology,and eight geometric primitives including node,edge,arc,triangle,supper-surface,GTP,tetrahedron and super-body are abstracted.The arc refers to an unclosed curve comprised of two or more end-to-end edges,the supper-surface refers to a spatial surface represented by a group of triangles in order,and the supper-body is a spatial region enclosed by a few supper-surfaces or formed by a group of adjacent GTP elements.The geo-entity is 0-3D classified into point entity,line entity,face entity and body entity,and the body entity could be furthermore sorted as simple body entity,compound body entity and complex body entity.A GTP-based entity model(GTP-EM) is presented for underground real 3D integral representation and modeling.With object-oriented method,the topological relations are defined by geometrical elements.With the 3D integral geo-entity representation and modeling for the subway and its surrounding strata located underground,the central business district(CBD) in Beijing city is taken as an example.