Research On Geographic Hypermedia Data Model And Web Service

Geographic representation, the fundamental issue in geography, is one of the key research topics in geographical information science. In the context of increasing popularity of geographic information, there exist representational challenges such as the bird's eye view versus the perspective view of geospatial reality, the abstract modeling approach to geographic information as opposed to the visual-spatial approach and the application design for professional or general public. The traditional multimedia map, combining map and multimedia elements, represent the geographic world more visually. With the rapid advance of the multimedia and position technology, the new-style geo-tagged media, such as geographic video, panoramic picture and measurable image, have been introduced in GIS applications. Geographic hypermedia attempts to provide a new way for rich, open, flexible and interactive multimedia geographic representation.This paper aims to introduce the stereo video to geographic information science. The data model, data management, web service and application of geographic stereo video are discussed in detail. The research topics include: (1) The system design of geographic hypermedia framework including system architecture, data organization, integration technology; (2) The data model for geographic stereo video, and related data collection, processing and management; (3) The design and implementation of web services for geographic stereo video, including service mechanism, interface and programming technology; (4) The development of geographic hypermedia systems to test the feasibility of geographic stereo video data model and web service introduced in this paper. The major research progresses are summarized as follows:(1) The framework design for geographic hypermedia. The content, functions, standards, technologies and application of geographic hypermedia was discussed in detail. A geographic hypermedia document data model (GHDocObject) and the integration framework of geographic hypermedia based on SOA were designed. The GHDocObject model supports general application functions, such as map and multimedia visualization, querying and image measurement.(2) Introduction of a geographic stereo video data model (GeoSVDM). The model was composed of entities of video, geometry, theme, semantic annotation and linear reference. The model objects and their relations were defined in Unified Model Language carefully. At logic levels, 12 core relation tables, the semantic schema and data retrieve methods were designed for application purpose.(3) System integration for geographic stereo video data acquisition and processing. The video and geospatial data were collected using a laptop with stereo camera, 3D compass and GPS receiver, and processed using image rectification and disparity calculation library. The related algorithms, such as field of view (FOV) polygon generation and 3D point cloud processing were designed according to GeoSVDM.(4) The geographic stereo video Web Service design and implementation. The resource identification, URI definition, resource operation interface and resource representation format were discussed in detail. The service interfaces and HTTP interaction for retrieval service, video playing service and image measurement service were defined on the basis of industry standards. All the web services were implemented via Windows Communication Foundation (WCF) technology.Based on the geographic stereo video service, web mapping service and browser-side AJAX programming, a geographic hypermedia system for Henan University (Jinming campus) was developed. The data collection, processing, management and application development indicated that the geographic hypermedia framework, geographic video data model (GeoSVDM) and web services introduced in this paper are feasible and flexible. These technical solutions are practical for the development of geographic hypermedia applications. Furthermore, this paper provides a new approach to manage and utilize geo-tagged media in geographic hypermedia framework, and will expand the multimedia geographic representation.