Embedding Production Rules in a Geographic Information System

David Pullar
Department of Geographical Sciences and Planning, University of Queensland, Brisbane, AUSTRALIA. Q4072

Geographic information systems (GIS) have evolved as a general solution for managing and analysing spatial data. GIS is used in numerous applications areas; built environment, natural environment, and business. Having such general applicability has meant that GIS data models have historically remained very generic. The geo-relational model (Morehouse, 1985) is still the most prevalent data modelling approach for building real world applications. The drawback is that application developers must map from domain knowledge to the geo-relational model. And then it is left to the application code to maintain domain-specific operations and integrity constraints. Users want more sophisticated models to build GIS applications. The problem is how to move from "generic and simple" data models to more expressive "semantic models" (Morehouse, 1990).

The solution is to include knowledge-based models in information systems. Two common technologies to do this are:

OOP and rule-based programming are both popular programming paradigms. Each being employed in GIS applications in different contexts. Our work has investigated a synthesis of these two paradigms. The paper describes a prototype that embeds an inference engine in a GIS, namely Arcview from ESRl. The aim of the research is to provide a generic approach to incorporating procedural knowledge in a GIS. We store rules in an object database, and associate the rule identifier with application documents and controls. All rules are expressed in Arcview's OOP language.

Specifically the paper discusses:

Lowes, D. and Bellamy, J.A. 1994. "Object Orientation in a Spatial Decision Support System for Grazing Land Management", AI Applications, 8(3).

Morehouse, S.D. 1985. "ARC/INFO: A Geo-Relational Model for Spatial Information", Proceedings Auto-Carto 7, Washington, 1985

Morehouse, S.D. 1990. "The Role Of Semantics In Geographic Data Modelling", Proceedings 4th International Symposium on Spatial Data Handling, Zurich, 1990.

Wright, J.R., Wiggins, R.K., Jain, R.K. and Kim, T.J. 1993. Expert Systems in Environmental Planning. Springer-Verlag