Spatial DBMS Spatial Database Management Systems Introduction SDBMS

Spatial DBMS Spatial Database Management Systems

Introduction SDBMS is a database system with additional capabilities for handling spatial data. • Spatial Objects • • • Consist of points, lines, surfaces, volumes and higher dimension objects that are used in applications of computeraided design, cartography, geographic information systems. Spatial Data • March 2002 The values of the objects’ spatial attributes: length, configuration, perimeter, area, volume, etc. Spatial Databases • A collection of spatial and non-spatial data that is interrelated, of data descriptions and links between data April 2004

Functionality • Spatial data is comprised of objects in multidimensional space • Spatial Indexing • Retrieving objects in a particular area without scanning the entire space • Spatial Joins • Efficient algorithms for joining multiple spatial objects

Raster and Vector Data • Two very different types of data • Vector is spit into three primary types: • polygon, line, point • Raster data represents the fourth type of feature: surfaces • Eg: thematic data, spectral data, and pictures (imagery)

Spatial Relationships • Topological relationships • Eg: adjacent, in, touch, equal, cover, overlap, disjoint, etc. • Direction relationships • Eg: above, below, north of, southeast of, etc. • Metric relationships • Eg: distance, size, perimeter, etc.

Querying • Spatial Selection • Eg: “All rivers in Arkansas” or “All rivers within 50 miles of Little Rock” • Spatial Join • Eg: “For each river in Arkansas, find all cities within 20 miles”

Indexing • • Organized so that only parts of the objects need to be examined to answer a query Data stored as either points or polygons Query types for points: • All points within a rectangle, point closest to query point, find points matching x in increasing distance from query point Query types for polygons: • • Intersection Containment