| An integrated soil information system was designed and implemented using an object-oriented approach. The system integrated the data of the soil table, soil taxonomy, digital elevation, and remotely sensed images collected in a study area at Little Lost Creek, Terre Haute, IN. Microsoft Windows and related development tool kits were used to build three object-oriented data base management systems (OODBMSs) to handle basic objects such as tabular data, cartographic maps, and images. Complex objects composed of multimedia data were simulated by cooperative working of the three OODBMs. The study addressed the issue of the object-oriented approach to an integrated soil information system design and implementation. It focused on a basic question of automated geography as how GIS developed without sufficient knowledge of future applications could be extended and integrated to meet unforeseen needs. Basic concepts of object-oriented spatial data model (OOSDM), data abstraction, and OODBMs were fully explored.;Object-Oriented framework (OOF), dynamic linking (DLK) and inter-object communication (IOC) were methodologies utilized to implement object-oriented data integration and system integration. OOF provides the foundation of integrative system design and implementation. DLK binds data and the related code at the time of execution, so that a specific code stored in dynamic link libraries (DLLs) can be supplied or updated along with application evolution. IOC based on a client-server model is applied by cooperative tasks which simulate the behavior of a complex object by message passing.;Significant contributions have been made to object-oriented GIS design and implementation, which include: (1) the accomplishment of the OODBMSs (TBASE, VIEW, and MAPS) using the methods of DLK and DLLs in a system-independent OOF; (2) the design and implementation of the IOC protocols solving the problems of the complicated system integration; (3) the design and implementation of the TBASE as an object-oriented RDBMS to support the virtual table and the user-defined predicates for tabular data manipulation. |
