Spatially-enabled databases

In a sense, almost any database can be used to store geospatial data: simply convert a geometry to WKT format and store the results in a text column. But while this would allow you to store geospatial data in a database, it wouldn't let you query it in any useful way. All you could do is retrieve the raw WKT text and convert it back to a geometry object, one record at a time.

A spatially-enabled database, on the other hand, is aware of the notion of space, and allows you to work with spatial objects and concepts directly. In particular, a spatially-enabled database allows you to do the following:

• Store spatial datatypes (points, lines, polygons, and so on) directly in the database, in the form of a geometry column.

• Perform spatial queries on your data. For example:

  select all landmarks within 10 km of the city named "San Francisco"

• Perform spatial joins on your data. For example:

  select all cities and their associated countries by joining cities and countries on (city...