Geo-SAL: A query language for spatial data analysis

Abstract

Conventional query languages focus on the retrieval and modification of data from a database to a user or a host program. Queries are usually expected to be relatively uncomplicated, leaving deeper processing functions to specialized host programs. In contrast with this view, the language SAL [Arnb80] was designed with the goal of being able to support stepwise, in-depth analysis of data, stored and managed as relations in a specially designed statistical database system, Cantor [Kara86]. This paper surveys the design objectives, operators and grammatical structures of Geo-SAL, a successor of SAL being developed for spatial data analysis purposes. In addition to facilities needed for representation and retrieval of spatial data, Geo-SAL includes primitives and structures which permit the solution of complex, multi-step spatial analysis problems within a coherent, declarative language.