Indexing and Browsing Digital Maps with Intelligent Thumbnails

摘要

With the increasing number of digital maps and other geo-referenced data that are available over the Internet, there is a growing need for access to techniques that allow us to preview the content and to evaluate it relative to the requirements for complex spatial and thematic queries. . Analogous to the digital indices for full-text searches on text documents we introduce highly condensed, machine-readable indices of digital maps. The purpose of these "intelligent thumbnails" is to support sophisticated queries of the type concept@location. An intelligent thumbnail is based on a projection of the thematic content of a digital map onto a standard reference tessellation. To make the thumbnail exchangeable in a distributed and heterogeneous environment, the underlying Standard Reference Tessellation (SRT) is qualitatively abstracted from a polygonal representation to a connection graph. In combination with a hierarchical place name structure and concept ontology, it is used to evaluate the spatial and thematic relevance of the indexed data sources with respect to spatio-thematic queries.