You also can use NoSQL databases to store geographic data:

 - **[MongoDB][1]** supports two-dimensional [geospatial indexes][2].
 - [GeoCouch][3] is an extension to **[Apache CouchDB][4]** that adds two-dimensional spatial indexing support.
 - [Neo4j Spatial][5] is a library of utilities for **[Neo4j][6]** that faciliates the enabling of spatial operations on data.
 - [SimpleGeo built a Scalable Geospatial Database][7] with **[Apache Cassandra][8]**.


  [1]: http://www.mongodb.org/
  [2]: http://www.mongodb.org/display/DOCS/Geospatial+Indexing
  [3]: http://docs.couchbase.org/couchbase-geocouch-guide/
  [4]: http://couchdb.apache.org/
  [5]: http://wiki.neo4j.org/content/Neo4j_Spatial
  [6]: http://neo4j.org/
  [7]: http://www.readwriteweb.com/cloud/2011/02/video-simplegeo-cassandra.php
  [8]: http://cassandra.apache.org/