A database model for heterogeneous spatial collections: Definition and algebra

Spatial DBMSs usually extends the classical relational model with data types for georeferenced data, providing a suitable extension of SQL. Designing a database for heterogeneous technological infrastructures may be hard, and queries may be hard to write and low to execute. We define a data model able to model, in a natural way, heterogeneous collections of spatial objects. The query algebra provides new operators able to naturally express complex queries on heterogeneous collections, by automatically deriving spatial descriptions from the composition relationships.