CONSIDERATIONS FOR THE DESIGN OF A MULTIPLE REPRESENTATION GIS

Maintenance of a multiple representation GIS using data from a variety of sources at differing scales requires update processing that can recognise equivalences and differences between new data and stored representations. Factors that may be taken into account when establishing equivalence and difference include a) measures of similarity of the location of new and stored geometry, having regard to positional error; b) comparison of classification and names; and c) comparison of geometric shape parameters. Decisions about update of representations of equivalent real-world phenomena may depend upon the capabilities of automatic generalisation procedures that could be used to derive one scale of representation from another. Access to data at different levels of detail, for answering queries and for processing updates, is facilitated by the use of multiresolution data structures