DCbot: exploring the Web as value-added service for location-based applications

Location-based services (LBS) are typically mobile applications that adapt their behavior to the spatial context of the user, e.g. by providing maps and navigational information of the user´s current position. Existing location-based applications rely on spatial data that is gathered and preprocessed especially for them and that is stored by particular data providers. Location-based applications can benefit from World Wide Web and additional information source, if, in a preprocessing step, Web pages are mapped to locations. A model for this is virtual information towers (VIT), spatial Web portals with a location and a visibility area that represents the region where the information is relevant. DCbot processes HTML pages in the WWW like a crawler of a search engine. It analyses the pages using pre-defined rules and spatial knowledge and maps them to locations.