spatial data management

1. Spatial Database
Management Systems

2. Introduction
SDBMS is a database system for handling spatial data.
 Spatial Objects
 Consist of points, lines, surfaces, volumes and higher dimension
objects that are used in applications of computer-aided design,
cartography, geographic information systems.
 Spatial Data
 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
March 2002
April 2004

3. Functionality
 Spatial data is comprised of objects in multi-dimensional
space
 Spatial Indexing
 Retrieving objects in a particular area without scanning the
entire space
 Spatial Joins
 Efficient algorithms for joining multiple spatial objects

4. 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)

5. 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.

6. 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”

7. 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

8. THANKS