Geospatial database
A spatial database is a database that is optimized for processing spatial data . It differs from conventional databases in that additional data types are introduced , which are usually based on the Open Geospatial Consortium (OGC) standard . Spatial databases are often created by expanding classic database systems with appropriate software. Well-known versions are PostGIS , SpatiaLite and Oracle Spatial and Graph .
functionality
In addition to classic SQL commands, spatial databases make it possible to use spatial queries to analyze relationships between geometries or to create new geometries. The OGC defines the following types of commands:
- Measurements: calculation of lengths, areas, distances, etc.
- Functions: Modification of objects by creating buffers , convex hulls etc.
- Predicates: Check for conditions such as overlaps, maximum distance, etc. with return of Boolean values
- Constructions: Creation of new geometries, usually by specifying edge points
To represent relationships between objects, the Dimensionally Extended nine-Intersection Model (DE-9IM) is often used, which defines nine possible topological relationships between two geometries.
Spatial indexes
Since conventional index structures are not very suitable for spatial data, special spatial index structures are used to enable geometries in a database to be found efficiently. Frequently used implementations are for example:
literature
- Thomas Brinkhoff: Geodatabase systems in theory and practice: Introduction to object-relational geodatabases with special consideration of Oracle Spatial . 3. Edition. Wichmann, Berlin 2013, ISBN 978-3-87907-513-3 .