基于几何元素的城市三维地理信息系统空间数据模型

Spatial Data Models of 3D UGIS Based on Geometric Primitives

空间数据模型是城市三维地理信息系统建立的核心问题。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十八个空间数据模型:把空间现象抽象为六类对象:点对象、线对象、规则面对象、规则体对象、不规则对象和DTM,基于六种几何元素(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九个空间数据模型;把空间现象抽象为五类对象:0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,基于六种几何元素的不同组合提出了八个空间数据模型;把空间现象抽象为0维对象(点对象)、一维对象(线对象)、二维对象(面对象)、三维对象(体对象)、DTM,基于点、直线段、TIN面片、多边形、规则面、不规则面六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,表明了模型的特点及可行性。

Spatial data model is the core problem of building 3D UGIS. In this paper, eighteen spatial data models of 3D UGIS are presented and developed based on different dividing methods of city objects. Firstly, spatial phenomena are abstracted into six types of object classes which are point object,line object,regular surface object,regular body object,irregular object and DTM. Based on different combination of six geometric primitives (point,line,polygon,function construction surface,TIN facet,regular body primitives),nine spatial data models for 3D UGIS are presented. Secondly, Spatial phenomena are abstracted into five object classes which are 0D spatial object (point object),1D spatial object (line object),2D object (surface object),3D object (body object) and DTM, eight spatial data models are presented based on different combination of six geometric primitives. Finally, Dividing spatial phenomena into five object classes which are 0D object (point object),1D object (line object),2D object (surface object),3D object (body object) and DTM,one spatial data model is presented based upon six kinds of geometric primitives: point,line,TIN facet,polygon,regular surface and irregular surface. Characteristics of all models and their feasibility are showed through verifying a model and analyzing all the models.