A semantic web map mediation service: interactive redesign and sharing of map legends

Abstract

We describe a semantically-based Web Map Mediation Service (WMMS) that allows researchers to define, capture and reuse semantic relationships between map categories, via a set of Web Services. A map can then be viewed according to different taxonomies or legends, whose categories have been semantically related to those native to the map. Such 'mappings' or 'mediation schema' can be constructed directly between maps, or can utilise an independent 'master schema' such as an application ontology, to which map categories are aligned. This paper explains the workings of the Mediation Service that allows users to: (i) experiment with the design of map classification schemes, (ii) explore how the use of different schemes affects what is apparent on the map and (iii) translate maps---as far as possible---from one classification scheme to another. Semantic equivalences and similarities are supported via underlying ontologies, and it is these that facilitate the merging and re-grouping of classes. Users can create their own map re-classification schemes, which can be serialized for later use. They can also create and share new versions of existing maps that have been reclassified according to the mediations that they specify. Examples are provided of mediations to support the combined use of three different land cover maps used in New Zealand, each with a different set of base categories. The service shows promise in extending the useful life of historical data, by allowing communities to build and share schemas that re-express older map legends.