基于几何元素的城市三维地理信息系统空间数据模型

空间数据模型是建立城市三维地理信息系统的核心问题。基于不同的城市空间对象划分方法 ,提出了城市三维地理信息系统的 18个空间数据模型 :①把空间现象抽象为点对象、线对象、规则面对象、规则体对象、不规则对象和DTM等 6类对象 ,基于 6种几何元素 (点、直线段、多边形、函数构造面、TIN面片、规则体素 )的不同组合 ,提出了城市三维地理信息系统的 9个空间数据模型 ;②把空间现象抽象为 5类对象 ,分别为零维空间对象 (点对象 )、一维空间对象 (线对象 )、二维空间对象 (面对象 )、三维空间对象 (体对象 )和DTM ,基于 6种几何元素的不同组合提出了 8个空间数据模型 ;③把空间现象抽象为零维对象、一维对象、二维对象、三维对象和DTM ,基于点、直线段、TIN面片、多边形、规则面、不规则面等 6类几何元素提出了一个空间数据模型。通过对一个数据模型的实验验证和各模型的理论分析 ,说明了这些模型的特点及可行性。

Spatial data models of 3-D geographic information system based on geometric prim itive elements

Spatial data model is the key for constructing 3-D ultra geographic information system (UGIS). Eighteen spatial data models for 3-D UGIS were developed on the different methods for dividing city objects. Firstly, spatial phenomena were abstracted into six types of objects including point object,line object,regular surface object,regular body object,irregular object and DTM. On the basis of different combination of six geometric primitive elements including point,line,polygon,function construction surface,TIN facet and regular body primitives,nine spatial data models for 3-D UGIS were presented. Secondly, spatial phenomena were abstracted into five objects of 0-D spatial object (point object),1-D spatial object (line object),2-D object (surface object),3-D object (body object) and DTM, and eight spatial data models were presented on the basis of different combination of six geometric primitive elements. Finally, spatial phenomena were divided into five objects of 0-D object (point object),1-D object (line object),2-D object (surface object),3-D object (body object) and DTM,and a spatial data model was presented based upon six kinds of geometric primitive elements including point,line,TIN facet,polygon,regular surface and irregular surface. The characteristics and feasibility of all models were discussed by means of verifying a model and analyzing all the models.