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.