Mysql Spatial and Postgis - Implementations of Spatial Data Standards

Spatial databases have become a very important domain of databases recently. A standardization of the storing and analyzing methods provides consistency of data, makes it easier to combine these data and allows to integrate projects. There is a problem of standardization for leading public domain databases with spatial extensions described in this article. The two main standards - OGC OpenGIS and SQL/MM are presented. The consideration focuses primarily on two databases: PostgreSQL + PostGIS and MySQL Spatial. The problem of standard implementation is the main issue. The way of integration spatial extension with database system is described. The level of standard implementation is discussed. Examples for analytical functions are given. Several available language constructions of creating queries are presented. The integration and implementation level of presented spatial extensions differs. MySQL Spatial is well integrated, but realizes only part of OGC OpenGIS standard. PostGIS implements two standards almost entirely, but there way of spatial database creating is much more complicated. The considerations are illustrated with examples in SQL.