Geodatabases

Enterprise spatial database: PostgreSQL/PostGIS

PostgreSQL is a powerful enterprise-level Open Source database with 15 years of active development and an architecture with a strong reputation for reliability, data integrity and performance. PostgreSQL runs on all major operating systems including GNU/Linux, UNIX (AIX, BSD, HP-UX, SGI IRIX, Mac OS X, Solaris, Tru64) and MS Windows. More info.

PostGIS is an extension of PostgreSQL, allowing PostgreSQL to support geographic objects. PostGIS effectively allows a PostgreSQL server to be used as a backend database for geographic information, similar to the ESRI SDE or Oracle spatial extensions. PostGIS follows the "Simple Features Specification for SQL" OpenGIS specification.

Some of PostGIS' features include:

• Intuitive graphical user interfaces (for example, pgAdmin III)
• Topology support
• Data validation
• Coordinate transformation
• A wide range of geoprocessing capabilities
• API (application programming interface)

Personal Geodatabase: SQLite/SpatiaLite

SQLite is a popular DBMS. It's simple, robust, very lightweight and easy to use. Each SQLite database is simply a file; you can freely copy it, compress it and send it over a network with no complication at all. The databases are also portable; the same database file will work on MS Windows, GNU/Linux, Mac OS X, BSD, etc. 

The SpatiaLite extension allows SQLite to also support spatial data [aka GEOMETRY], in a way that conforms to OpenGIS specifications and supports standard WKT and WKB formats.

It implements SQL spatial functions such as AsText(), GeomFromText(), Area(), PointN(). The complete set of OpenGIS functions, such as Overlaps(), Touches(), Union() and Buffer() are supported via the GEOS library. SpatiaLite supports full spatial metadata according to the OpenGIS specifications, supports importing and exporting from / to shapefiles, supports coordinate reprojection via PROJ.4 and EPSG geodetic parameters and supports local character sets via GNU libiconv.

SpatiaLite implements a true Spatial Index based on SQLite's RTree extension and the VirtualShape extension enables SQLite to access shapefiles as VIRTUAL TABLEs. Standard SQL queries can then be performed on external shapefiles with no need for importing or converting them. The VirtualText extension allows SQLite to also access CSV/TxtTab files as VIRTUAL TABLEs. Standard SQL queries can then be performed on external CSV/TxtTab files, with no need for importing or converting them as the GUI tool supports all these features in a user friendly manner.