Transmitting Vector Geospatial Data across the Internet

Transmitting geospatial data via the Internet has become commonplace, and relies upon a raster data model that proves efficient for imagery, orthophotography, and satellite data products. Internet transmission of vector geospatial data remains a challenge. The content and geometry of vector data change with resolution, and this aspect of scale-dependence must be accounted for in transmitting vector data across the Internet. Progressive transmission of vector data can be accomplished using sound principles of existing cartographic theory, such that a less detailed representation can be amplified with finer levels of detail. Amplification must transmit actual data, as originally compiled, rather than adding detail that is interpolated or derived. The paper presents design and implementation of an algorithm that transmits vector coordinates at progressive levels of resolution, preserving geometric and topologic properties. The transmission is intended to serve subsequent data processing in a GIS environment, with online display as a secondary goal.