A Knowledge-Based Systems Approach to Design of Spatial Decision Support Systems for Environmental Management XUAN ZHU* Department of Geography University College Cork Cork, Ireland RICHARD G. HEALEY Department of Geography University of Portsmouth Portsmouth PO1 3HE, UK RICHARD J. ASPINALL GIS and Remote Sensing Unit Macaulay Land Use Research Institute Aberdeen AB9 2QJ, UK ABSTRACT / This paper describes a framework for design- ing spatial decision support systems for environmental man- agement using a knowledge-based systems approach. An architecture for knowledge-based spatial decision support systems (KBSDSS) is presented that integrates knowledge- based systems with geographical information systems (GIS) and other problem-solving techniques. A method based on spatial influence diagrams is developed for representation of environmental problems. The spatial influence diagram pro- vides an interface through which knowledge-based systems techniques can be applied to build capabilities for problem formulation, automated design, and execution of a solution process. In addition to the flexibility and developmental ad- vantages of knowledge-based systems, the KBSDSS incor- porates expert knowledge to provide assistance for structur- ing spatial influence diagrams and executing a solution process that automatically integrates the GIS, data base, knowledge base, and different types of models. The frame- work is illustrated with a system, known as the Islay Land Use Decision Support System (ILUDSS), designed to assist planners in strategic planning of land use for the develop- ment of the island of Islay, off the west coast of Scotland. The use of computer-based systems in support of decision making in environmental management has increased dramaticallyover the past decade. Geographi- cal information systems (GIS), knowledge-based sys- tems (or expert systems), and other problem-solving techniques have been used to help environmental scientists understand and control complex biological and physical systems. At the same time, there has been a great deal of research on the development of spatial decision support systems (SDSS). An SDSS aims to provide a decision-making environment that incorpo- rates the data storage, computation, and analysis capa- bilities of modern computers to support decision mak- ers in making decisions effectively for environmental management. The design and implementation of SDSS has pre- sented many challenges (Abel and others 1994). A traditional approach to the design of SDSS is to define architectures that assemble a set of components, includ- ing data-base management systems, spatial modeling, analytical models, graphical display, and tabular report- ing (Armstrong and others 1986). Given the spatial nature of environmental management problems, many SDSS have been designed and implemented using GIS technology, coupled with specific analytical modeling techniques and models (for examples, see Walker and Moore 1988, Pearson and others 1991, van der Vlugt 1989, Negahban and others 1993). These approaches put emphasis on information access and displayand on numeric computation byanalytic models. However, the problem-solving tasks in environmen- tal management require integration, interpretation, and deliveryof different representations of knowledge, including heuristic knowledge of human experts, and analytic modeling results. For example, the resolution of rural land use conflicts within a region involves a fundamental trade-off between the physical suitability of the land for a given purpose and the environmental impacts of certain land-use patterns. There may be numerous suitability models addressing variations of this trade-off. However, other aspects may need to be considered. The interests of the local community may restrict new land-use development. Economic apprais- als of the different forms of land use may play a role. KEY WORDS: Geographical information systems; Spatial decision support systems; Knowledge-based systems; Spatial influence diagrams; Environmental management *Author to whom correspondence should be addressed. Environmental Management Vol. 22, No. 1, pp. 35–48  1998 Springer-Verlag New York Inc.