地理空间数据等积全球格网多模式三维扩展方法

Multi-mode 3D extension methods for equal-area discrete global grid systems for geospatial data representation

全球离散格网系统是新型地理空间数据组织框架,等面积格网由于在采样和空间分析方面的独特优势而备受关注,但相关研究囿于地球表面,缺乏扩展至三维广域空间的一般方法。本文首先提出将等积球面格网系统扩展为球体格网系统的多种剖分模式,并实现其统一数学描述和详细数学证明;然后引入体积和紧致度指标定量评价不同剖分模式的体元性质,并与球体退化八叉树格网(SDOG)、大圆弧八叉树格网(SGOG)作对比;最后初步探索了本文方法的应用案例,讨论了不同应用需求下选择剖分模式的原则。对比试验结果表明,退化剖分的体元各项指标均优于规则剖分,等体积和退化剖分的体积性质优于SDOG,紧致度性质优于SGOG。本文多剖分模式三维扩展方法不仅符合国际标准等体积的要求,而且兼顾常规剖分设计选项,为不同应用需求提供了参考依据。

Discrete global grid systems(DGGS)are new geospatial data models,among which the equal-area DGGS have attracted much attention due to their unique advantages in sampling and spatial analysis.Nevertheless,related researches are limited to the earth surface and lack of theoretical methods for extending to 3D space.Herein,several multi-mode subdivision methods are proposed for extending equal-area 2D DGGS to 3D DGGS and their unified mathematical description and detailed mathematical proof are realized.Then the volume and compactness indicators are introduced to evaluate the properties of 3D grids under different subdivision modes,and we compare these indicators with the spherical degenerated octree grids(SDOG)and the spherical geometric octree grids(SGOG).Finally,the application cases are explored and the principle of selecting subdivision mode under different application requirements is discussed.The experimental results show that the indicators of the degenerated subdivision are better than the regular subdivision and the volume properties of equal volume and degenerate subdivision are better than SDOG,and the compactness properties are better than SGOG.The multi-mode 3D extension method proposed here not only meets the requirements of international standard for equal volume,but also consider the conventional subdivision design options,which provides a basis for different application requirements.