The integration methods of 3D GIS and 3D CAD

Abstract

GIS (Geographical Information System) and CAD (Computer Aided Design) have evolved largely in the past 30 years. GIS and CAD describe the same real-world objects but they belong to different domains. The spatial and non-spatial data involved in the two systems are quite different and the two systems cater for different applications. With the advancement in information technology and 3D representation of geospatial information, more and more 3D applications demand both of them to be used together. This paper focuses on how to integrate the 3D GIS and 3D CAD. After reviewing the development of both the 3D GIS and 3D CAD systems, this paper compares their differences in the domain/purpose, coordinate system, object type, and so on. Then five approaches for the integration of 3D GIS and 3D CAD system are introduced, i.e. data exchange; direct data import; share the API of database; CAD-based GIS system/GIS-based CAD system; formal semantic and integrated data management. Basing on the first approach, this paper designs the scheme of integrating 3D GIS and 3D CAD systems with the considerations that CAD data maybe in a local coordinate system not compatible with GIS data; the information loss due to data translation; translating data between the complex geometric description in CAD and the simple geometric description in GIS and so on. According to this scheme, and based on VGEGIS software platform developed by LIESMARS of Wuhan University and AutoCAD 2006, a pro totype system is developed to demonstrate the integration of 3D GIS and 3D CAD.