The Research and Development of Manipulation Tool for Handling of Geographic Information

Abstract

Relational database languages could succeed in the market because they provided a high portability and interoperability between different DBMSs and they made users to learn new DBMSs easily through the standard query language, called SQL. The SQL can also be employed as a standard interface between client/server systems of the distributed computing environment. In this work, we designed and implemented a spatial query language, called GSQL, on the Gothic S/W. The standard SQL is extended for allowing of spatial operations in the expression of the query language. GSQL provides the following facilities: 1) user friendly interfaces 2) Attribute Restrictions 3) Attribute/Spatial Joins 4) Spatial Operators 5) Method Invocation 6) Path Expression 7) Repeated Queries 8) Interactive Queries 9) Aggregation Functions 10) Result Output (Screen, Text).

GIS application often needs different representations of a spatial data according to a user's viewpoint. For example, a traffic management system treats a road as a line that have a direction, but a road management system treat it as a polygon. This work have designed and implemented the Spatial View System to allow to us to define a view class derived from one or more base spatial classes. Spatial View can improve query processing time and relieves a burden to repeat complex queries. It also can be used as a mechanism to reduce a communications overhead in the future client/server GIS systems.