地球信息科学学报 ›› 2014, Vol. 16 ›› Issue (5): 691-698.doi: 10.3724/SP.J.1047.2014.00691

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特征约束六面体网格生成的改进栅格法

庞宇(), 郭飞*(), 李想, 何梅芳   

  1. 南京师范大学虚拟地理环境教育部重点实验室,南京 210023
  • 收稿日期:2013-11-28 修回日期:2014-01-08 出版日期:2014-09-10 发布日期:2014-09-04
  • 通讯作者: 郭飞 E-mail:pangyunjnu@163.com;guofei@njnu.edu.cn
  • 作者简介:

    作者简介:庞 宇(1991-),男,硕士生,研究方向为三维GIS建模模拟。E-mail:pangyunjnu@163.com

  • 基金资助:
    城市软土地区工程沉降建模模拟研究(40801147)

A Modified Grid-based Algorithm for Feature Constraints HexahedralMesh Generation

PANG Yu(), GUO Fei*(), LI Xiang, HE Meifang   

  1. Key Laboratory of Virtual Geographical Environment, Nanjing Normal University, Nanjing 210023, China
  • Received:2013-11-28 Revised:2014-01-08 Online:2014-09-10 Published:2014-09-04
  • Contact: GUO Fei E-mail:pangyunjnu@163.com;guofei@njnu.edu.cn
  • About author:

    *The author: CHEN Nan, E-mail:fjcn99@163.com

摘要:

目前,针对地学对象的非结构化六面体网格生成问题仍未得到很好的解决。为满足相关地学研究对六面体网格的需求,促进地学模拟及传统GIS空间分析的进一步发展,本文对传统栅格法进行扩展,提出了一种面向地学研究的六面体网格生成的改进栅格法。通过提取实体模型表面的几何特征,考虑内部孔、洞约束生成骨干网格,在此基础上构建一套特征约束模板来处理复杂的特征约束,使之既能保持地学研究对象的几何形态特征,又能实现加密区域与非加密区域的平滑过渡,从而满足地学分析与模拟的需求。

关键词: 特征约束模板, 地学分析, 六面体剖分, 改进栅格法

Abstract:

Currently the method of geoscience mechanism and process simulation is using 2D or 3D finite element mesh to discretize geographical space, and then complete the calculation and simulation with relevant numerical calculation method. Therefore, the finite element mesh subdivision is the basis to carry out the learning mechanism and process simulation. Traditional grid-based hexahedron generating algorithm uses a standard orthometric grid to cover the entire research area, deletes the meshes that lie outside the area or are intersected at the boundaries, and then fills the space between the border and the grid area. As a result, the research area are fullfilled with regular meshes inside the area and irregular ones on the border. However, the geological research subjects are generally characterized by complex boundary and contain more spatial feature contraints. Meanwhile, geosciences analysis and computation require meshes of higher quaility. Therefore, the existing hexahedron generating algorithm can not generate meshes with preferable discretization for geological research subjects. The paper presents a modified grid-based hexahedron generating algorithm taking the advantages of the traditional grid-based algorithm for geosciences analysis, in order to meet the requirements of relevant geoscience researches for hexahedron mesh, and to promote further improvements to the geoscience simulation and the traditional GIS space analysis that are based on numerical methods. The algorithm generates the backbone grid by extracting the geometrical characteristics of the surface model, which takes the constraints such as internal pores and caves into consideration. At the same time, it builds some templates to handle the complex feature constraints, in order to keep the geometric shape of these feature constraints, and to achieve a smooth transition between the refined area of feature constraints and the unconstrained part. Then it uses mesh quality optimization algorithm to improve the mesh quality. In the end, it is proved practically by an example of the geographic model of Nanjing south railway station. The algorithm can produce high quality hexahedron meshes which not only keep the geometrical form of characteristic for the geoscience research objects, but also fullfill the requirements of geoscience analysis process simulation.

Key words: feature constraints, geosciences analysis, hexahedral mesh generation, modified grid-based algorithm