The new 3DGIS for seamless integration of terrain overground and underground entities

The seamless integration of terrain,overground and underground entities is the principal symbol of up-to-date 3DGIS,and the seamless integrated spatial modeling has been an urgent demand.Based on the analysis of present technologic situation and issues on 3D spatial modeling,the goal levels and function demands for 3D spatial modeling and the present situation and developing trends of 3D spatial model,this paper introduces the two levels of integrated modeling for terrain,overground and underground entities as well as the primary principles for seamless integration.The notional structure and typically logical relations of a integrated spatial data model,which takes constraint delaunay triangulation network(CD-TIN) as a link,BRep-CDTIN-GTP as its core and three compound models as its components,is presented.As its application in city and mine being an example,the visualization effect of the new integrated model realized inside the 3D modeling system,GeoMo3D,is shown.In the meantime,the chief research directions and theoretical issues for 3DGIS related to seamless integrated modeling for the coming years are pointed out.