Maintaining Reality: Modelling 3D spatial objects in a Geo-DBMS using a 3D primitive

摘要: The objective of this thesis is answering the following question: How can 3D spatial objects be modelled (i.e. /stored, validated, queried) in a Geo-DBMS using primitives and how these visualised? To answer question theory from various literature used to create prototype implementation primitive Geo-DBMS. Spatial are stored with polyhedron as (3D) primitive. This easy for users model objects, fairly easily because algorithms not too difficult implement still result realistic objects. Each has set faces, which consist ordered nodes. These nodes point vertex (x,y,x). means that data geometric internal topology. Th epolyhedron within original Oracle geometry model. validation occurs by checking if polyhedra correctly after each characteristic polyhedra. characteristics are: flat should bound one volume, simplicit faces orientable. improve performance queries, index made on table standard indices used, way A bounding box constructed around line or its projection case 2D index. test shows it preferable (3D R-tree) rather than index, get maximal query performance. Using functions part Spatial, suitable work Instead, some most commonly (e.g. area, point-in-polyhedron box) implemented 3D, so return value. visualised GIS CAD programs make DBMS connection. do this, have exported multi-polygons. export function implemented, import makes multi-polygon. visualise polyhdra VRML viewer, database file. object. concousions together satify goal improves maintainability opens door more applications.