Answering a need for user-specific features
The user may express a need for a feature that should be derived through geographic information system (GIS) functions (e.g., isolated industrial buildings near my place, my way home).
To map such a need with the relevant data set, the catalog service needs a model of links between user features and queries for data and functions.
The task-based TAGE model introduced in Section 4.3.1 has been initially designed to meet this issue. The expression of a user need can be supported by specifying the corresponding generic task (e.g., “to determine the nearest beaches to my place” is expressed by specifying the task “to locate something”). This specification is the specification of a set of roles attached to the task as illustrated on Figure 4.7.
For instance, the user specifies the role “entity to locate” as follows: it is of feature-type “beach” and has a spatial relationship “nearest” with another user feature “my place.” The spatial relationship “nearest” refers to a driving distance. The feature “my place” may itself be specified as follows: it is referenced by a postal address, it is inside the “Morbihan” (French administrative entity), or it can be referenced by the user through clicking on a map.