| With the rapid development of spatial information application, the existing network access mode of spatial information already can't adapt the request of spatial information service and sharing. In order to manage and maintain complex spatial information efficiently and improve the efficiency of transmission and processing, There are urgent need for a new network access mode of spatial information and a practicable digital earth platform to be constructed, in which all kinds of problems correlated to spatial information may be observed, studied and solved. It also could make the spatial information technology towards the masses.In traditional network access mode of spatial information, for example, for C/S mode, the fat client may be applied to solve the considerably computing complexity but this mode can not meet the spatial distributed access and vice versa for B/S mode. So the article puts forward and establishes a new network access mode of spatial information named Geological Browser/Spatial Information Server (G/S) and also proposes a new Markup Language named Hyper Geographic Markup Language (HGML) by analogy with HTML of B/S mode. Then, G/S mode and HGML can be utilized to construct the standard and the format of representation, exchange, organizing and management. On the one hand, According to the standard described above, the distributed spatial information server cluster may be constructed to meet the downloading and transmitting service of spatial information with dynamic load balancing and a unified data format or standard. On the other hand, some functions such as dynamic access of spatial information, 3D presentation, spatial information query and spatial analysis can be realized by developing powerful, flexible, conveniently operational 3D geological information browser. The G/S mode can significantly obtain the solution to some problems from spatial information network access, such as complexity in space, computation and network and it also can enhance the quality and efficiency of spatial information sharing and services.G/S mode constructs an integrated computation and resource environment. Its greatest advantage is to realize the sharing truly by using various kinds of resources and all types of functions sufficiently and obtain much more benefits and achievement. Digital earth platform provides a place physically for resource sharing. Numerous users share resources and accept services of same kind. Users can obtain multiple spatial information resources at the same time or receive various kinds of resources to meet the complicated requirement.HGML, namely Hyper Geographic Markup Language, is the main language to construct spatial information of G/S spatial information management mode. Its purpose is to establish the connections among spatial data stored in distributed server and form into an organic whole without considering concrete data on what position of network. HGML text is a descriptive text composed of HGML command. HGML command can account for spatial object including point, line, surface, raster data, image data and attribute data. HGML structure is composed of GeoHead and GeoBody where the GeoHead gives the information the browser needs while the Geobody shows the concrete content explained. HGML is an extension of HTML, and it is simple general Markup Language. It allows the complicated page with spatial graphics to be established by word processor (For instance, Microsoft Word\Notepad\WordPad etc.) and explained by G terminal of G/S mode.Users and physical resources are distributed in wide areas and different geographical position. The whole spatial information likes'one computer'through virtual interface provided by digital earth platform, although they are not visible mutually. Users access all kinds of spatial information resources seamlessly and transparently by a unified, standard, open and general HGML protocol. Different geographical position, different management platform, different database storage and resources originated from different channel and different ability could be integrated seamlessly and organically by the distributed server cluster. Besides, users can use single resource and function or use multiple resources and synthetic function by adjusting the resource users in different geographical position.Resources influx and full sharing of distributed spatial information is realized by Digital earth platform based on G/S mode. Distributing is the most important characteristic of digital earth platform. Spatial information resources are composed of different geographical position, various types of data, information, and knowledge. Because of the complicated and large-scale distribution of spatial information resources, all kinds of computation can not be realized in centralized station, so, distributed computation must be adopted. Network bottleneck of spatial information in B/S application is solved by moving computation and analysis of server station to G terminal.Another characteristic of digital earth platform is resources influx and full sharing. Various resources of spatial information is distributed, but any user can supply and use them by digital earth platform, and full sharing could be provided among different regions, different place, different platform and different exclusive system by digital earth platform . As the final purpose, resources influx and full sharing are the most important characteristics. And can be realized by distributed server cluster of server side and HGML sharing standard.The prototype system of UStar digital earth platform was constructed based on G/S mode framework and was applied to digital tourism project initially. The obtained results were satisfied.The proposing and fundamental application achievements of G/S mode indicate that G/S mode can provide the standard and feasible technology system framework for widely using of digital information over the network. G/S mode also provides technical references for service, management and application of future spatial information technology. It is a meaningful research.
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