Interfacing geographic information systems with agronomic modeling: A review

Agronomic models are traditionally used for point or site-specific applications due to limitations in data availability as well as computer technologies. Interfacing geographic information systems (GIS) with agronomic models is attractive because it permits the simultaneous examination of spatial and temporal phenomena. The objective of this review is to examine strategies for interfacing GIS with agronomic models. It considers the diverse terminology in use, programming approaches, issues of data and scale, and existing applications. Linking is defined as merely passing input and output between a GIS and a model, combining is defined as automatic data exchange and GIS tool functions, and integrating is defined as embedding a model in a GIS or vice versa. Due to differences in research objectives, spatial and temporal scales, data sources or formats, and the natural processes being modeled, there is no universal approach for interfacing. Because of the detailed input requirements for agronomic models, expanding the models from a point-based application to a spatial application can greatly increase the volume of input data. This review suggests that a major challenge in interfacing GIS to models lies in developing systems that handle spatial processes by implying interactions among spatial units. Moreover, extensive data requirements must be satisfied, while also ensuring data quality control.