Model validation and use of geographic information systems in crop protection warning service

Abstract

Validation is an essential part of the model development process if models are to be accepted and used in decision support systems. Validation ensures that the model meets its intended requirements in terms of the methods employed and the results obtained. The ultimate goal of model validation is to make the model useful in the sense that the model: addresses the targeted problem, provides accurate information about the system being modelled, and makes the model acceptable for practical use. This chapter describes the main validation methods used for models which are validated and currently used in the field by the German Plant Protection Service. Furthermore, the results of a study how to increase the accuracy of simulation models by using Geographic Information Systems (GISGIS) are presented. The influence of elevation, slope and aspect on temperaturetemperature and relative humidityrelative humidity were interpolated with GIS methods, whereas precipitationprecipitation data was obtained from radar measurements; these meteorological datameteorological data were used as input for the simulation models. The output of these models is presented as spatialspatial risk maps in which areas of maximum risk of a disease are displayed. The use of GIS methods to increase accuracy is expected to increase system adoption by farmers.