SPATIAL MAP DATA SHARE AND DISSEMINATION SYSTEM BASED ON DISTRIBUTED NETWORK SERVICES
D. Zhang1, L. Ailong2, W. Ling2, Y. Xuewei2, C. Tao2
1 - School of Electronics and Information Engineering, Xi’an JiaoTong University; Xi an research institute of sueveying and mapping, Map and GIS, Xi an, China
2 - Xi an research institute of sueveying and mapping, Map
and GIS, Xi an,
Spatial Map Data (SMD), with some characteristics such as mass data, multi-scales, universality and discrete distribution, is suitable to be processed in the network environment with distributive, sharing, self-adaptive, heterogeneous and expansive features. The Map Data Network Dissemination System （MDND） for disseminating SMD to remote users through network is presented. Firstly, SMD, associated metadata and network resource nodes described as a graphic form are defined. The relations between SMD and network resources are established. After giving formalized definition to MDND, SMD dissemination framework and a series of distributed CORBA services, conditions input methods based on three querying conditions are presented. MDND is implemented in the basis of metadata integrated querying service and SMD route-pointed service. Compared with the modes of CORBA service, FTP and Direct Copy, results show that SMD dissemination can be achieved effectively by the proposed system. The transfer performances of CORBA services mode is almost equal to direct Copy , obviously better than FTP evidently, and approaches to the biggest transfer rate more quickly and dependents on data amount weakly.