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This research paper explores the potential and performance of using the Oracle Spatial geo-DBMS to structure, index, query, and visualize spatiotemporal point clouds of moving objects. It discusses a generic model for moving object DBMS, static and dynamic modeling cases, and provides conclusions and recommendations.
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Moving objects in a geo-DBMS Structuring, indexing, querying and visualizing moving objects in a spatiotemporal DBMS Heraklion, Agile 2004 Marco Baars*, Peter van Oosterom, Edward Verbree, Ben Gorte OTB Research Institute for Housing, Urban and Mobility Studies Section GIS Technology
Content • Introduction of the subject • Generic model for moving object DMBS • Case I: static modeling • Case II: dynamic modeling • Conclusions and recommendations
Introduction • Spatiotemporal DBMSs become popular • Traffic jams, cadastral issues • Database is remained to stay constant • New challenge for moving objects in database • Databases useful for • Large datasets • Easy querying • Consistency, security, redundancy, interoperability
Introduction – Main question What is the potential and performance of the Oracle Spatial geo-DBMS to structure, index, query and visualize spatiotemporal point clouds of moving objects?
Introduction Vazirgiannis/Wolfson • Map • Moving object • Trajectory Characteristic: • Developed for specific application
Generic model Base table: CREATE TABLE mov_obj (id, t, geometry) –-prim.key = id,t
Generic model • Base table with (materialized) views CREATE VIEW move_obj_succ AS SELECT t1.*, t2.t as next_t FROM mov_obj t1, mov_obj t2 WHERE t1.id=t2.id and t2.t=(select min(t) from move_obj where t>t1.t); • Flexible, consistent and fast
Case I: Static modeling • Data (id,x,y,t) collected in advance • One “base table” with views in Oracle 9i Spatial • Querying based on operators and functions • Operator: sdo_relate • in where-clause • Index necessary • Function: sdo_geom.relate • Visualization (animation)
Case II: Dynamic modeling • Real-time simulation (growing table) • 2D and 3D indexing tests
Case II: Dynamic modeling • 2D Query “SDO_RELATE” • 3D Query “SDO_FILTER” x1,y1,t1 x0,y0,t0
Conclusions • Generic model is flexible, fast and consistent for static and dynamic point data • Choice for “base table” has to be made and depends on: • 2D or 3D queries • 2D or 3D index • Update time for index depends on covered area and number of objects in growing table
Future Research • Prove Generic Model for 4D data (x,y,z,t) • Test the ArcIMS Tracking Server • Implementing more efficient R-tree • Test model for polylines, polygons or polyhedrons