ABSTRACT
The main impediment to a widespread use of geographic information using a geographic information system (GIS) is the gap between the user’s expression of a task within the context of an activity and the sequence of operations within a GIS needed to successfully perform that task. Users express their intentions and supporting activities in a high level language, usually in natural language. This level corresponds to the knowledge level (Newell, 1982). Those activities need to be broken down into a sequence of tasks that exist in the head of the user and are part of her training as expert in the field. Each task has to be performed as a sequence of operations (according to a specific method), which can be carried out (mostly) by the commands and functions of an information system, e.g., a GIS or a Spatial Decision Support System. Depending on the complexity of the activity, more intermediate levels of tasks might be needed, creating sub-tasks.
