Map data network dissemination system based on metadata and CORBA services

Taking advantage of some characteristics of spatial map data (SMD), such as mass data, multi-scales, universality, and discrete distribution that is suitable to be processed in the network environment with distributive, sharing, self-adaptive, heterogeneous and scalable features, a map data network dissemination (MDND) system for disseminating SMD to remote users is presented. Firstly, SMD, the associated metadata and the network resource nodes described as a graphic form are defined. The relations between SMD and network resources are established. After giving formulized definition to MDND, SMD dissemination framework and series of services based on CORBA, the input methods are provided according to the three query conditions of metadata. MDND is implemented on the basis of metadata set inquiry service and route-pointed service of geographic information. Comparison in the modes of CORBA service, FTP and direct copy shows that the proposed system can effectively achieve SMD dissemination, its transfer performance in CORBA service mode is equivalent to the direct copy, better than FTP, and it approaches to the biggest transfer rate more quickly with weak dependence on data amount.