An integration approach to the management of geographical information: CARTECH

CARTECH, an SQL-based geographical information system, is presented. It is based on the integration approach, of coupling systems for dealing with traditional, descriptive data, with tools for the management of spatial data. Its key feature is the extension of the relational data model, to deal in a uniform way with both descriptive and spatial features of geographical information. The SQL language has also been extended in order to provide a uniform interface for processing both alphanumeric and spatial-geometric data. The architecture integrates the INGRES database management system for the treatment of non spatial data and the GEOTECH library for the management of spatial/geometric data. The article briefly describes the logical data model and focuses on architectural aspects of the developed integrated system, discussing the extended-SQL interpreter and query processor. An application of CARTECH to land resource management is presented and performances are discussed