Implementing an object-oriented error sensitive GIS

Despite considerable research interest in the handling of uncertainty within GIS, the production of what has been described as an error sensitive GIS is still some way off. The increasing use of objectoriented (OO) technology presents a variety of opportunities, but also impediments to the implementation of such an error sensitive GIS. An important barrier stems from the lack of homogeneity within languages and systems which are called ‘object-oriented’, as most exhibit widely different forms of object-orientation. Features such as multiple inheritance, static behaviour and polymorphism are not supported equally across different systems. The paper sets out a new OO approach to uncertainty handling, which defines the features of an OO uncertainty storage model fundamental to any error sensitive GIS implementation. Building on this as a generic framework for uncertainty handling, the uncertainty storage model is implemented within Java OO programming language and within LaserScan Gothic OO GIS. Finally, a mathematical formalisation of OO systems is used to examine the different mechanisms which each OO system supports and their effects upon the object-oriented model of uncertainty.