A SPATIAL/TEMPORAL QUERY LANGUAGE FOR MULTIPLE DATA SOURCES IN A HETEROGENEOUS INFORMATION SYSTEM ENVIRONMENT
Shi‐Kuo Chang, Erland Jungert · International Journal of Cooperative Information Systems · 1998
To support the retrieval, fusion and discovery of multimedia information, a spatial/temporal query language for multiple data sources is needed. In this paper we describe a spatial/temporal query language, the ∑QL, which is based upon the σ-operator sequence and in practice expressible in an SQL-like syntax. The general σ-operator and temporal σ-operator are explained, and applications of the σ-query language to vertical/horizontal reasoning and hypermapped virtual world are discussed.