A prototype system for propagating updates between cartographic data sets

This paper describes a prototype system for the propagation of updates between cartographic data sets at different scales. The prototype system is based on object-oriented techniques and a multiple representation database. The latter consists Of a master and a target data set together with connectivities between those objects referring to the same physical entities. The prototype is based on a conceptual framework of four steps: examination, propagation, generalization of updates and solution of spatial conflicts. The rules in these steps are triggered when an object is Edited in the master data set. In the examination step it is determined which object should be created, deleted or modified in the target data sri according to certain rules. In the propagation step the outcome of the examination step is executed. In addition, in this step the integrity of the multiple representation database is maintained, e.g. connectivities between related objects are set. In the third step the new or modified object in the tar-get data set is generalized to suit the scale of the target data set. Finally, in the last step the constraint method is used to solve the spatial conflicts caused by the update. The paper concludes with a case study. where a map produced by the prototype system is compared to a map produced manually by cartographers.