【作者】 俞晓；

【导师】 苗放；

【作者基本信息】 成都理工大学 ， 地球探测与信息技术， 2009， 博士

【摘要】 随着空间信息应用需求的迅猛增长,现有的空间信息网络访问模式已经不能很好地适应空间信息的共享和服务要求。为了高效的对复杂的空间信息进行管理和维护,提高传输访问和处理效率,迫切需要有一种新的空间信息网络访问模式,以及全新、实用的数字地球平台,以观察、研究和解决各种空间信息相关的各类问题,使空间信息技术走向大众。传统的空间信息网络访问模式中,C/S模式采用专用胖客户端解决计算复杂度问题,但无法很好的解决空间分布式访问问题;B/S模式瘦客户端,解决了数据的分布式访问,但无法很好的解决复杂运算的速度与效率问题。因此论文研究提出并建立一种称之为地学浏览器/空间信息服务器(G/S)的新型空间信息网络访问模式,并类比于B/S模式的超文本标记语言HTML,提出和建立针对空间信息地理数据的超地理标记语言HGML,构成空间信息的表现、交换、组织和管理的标准和格式。据此,一方面构建分布式空间信息服务器群,提供统一数据标准和动态负载均衡的空间信息下载和传输服务,另一方面,开发功能强大、配置灵活、操作方便的三维地学信息浏览器,通过网络实现空间信息的动态访问、三维表现、空间信息查询和空间分析等功能。该模式将极大地改善空间信息网络访问存在的空间复杂度、计算复杂度及网络复杂度等问题,可以有效提高空间信息共享和服务的质量与效率,具有重要意义。G/S模式构建了一个集成的计算与资源环境,其最大优势是充分利用各种资源和各类功能,实现真正意义的共享,从而产生更大的效益或绩效。数字地球平台在物理上为人们提供了一个资源共享的场所,众多的用户通过数字地球平台共享资源,接受同类功能的服务;G端强大的空间信息分析与运算能力,使用户可以同时使用多个空间信息资源,或接收多种资源的服务,从而满足复杂需求。HGML(Hyper Geographic Markup Language)即超地理标记语言,是G/S空间信息网络访问模式中构建空间信息的主要语言。其目的是为了能把存放分布式服务器上的空间数据方便地联系在一起,形成有机的整体,不用考虑具体的空间信息是在网络的哪个位置。HGML文本是由HGML命令组成的描述性文本,HGML命令可以说明空间对象,包括点、线、面、栅格数据,以及影像和属性数据。HGML的结构包括头部(GeoHead)、主体(GeoBody)两大部分,其中头部描述浏览器所需的信息,而主体则包含所要说明的具体内容。HGML是HTML的扩展,是一种简单、通用的全置标记语言。它允许建立结合空间图形的复杂页面,通过文字处理器(如Microsoft Word\记事本\写字板等等)来建立,通过G/S模式下的G端来解释。数字地球平台的用户和物理资源是分布在广泛区域、不同地理位置的。虽然它们之间互不可见,但通过数字地球平台提供的虚拟化的接口,使得整个空间信息“如同一台计算机”一样。用户使用统一、标准、开放、通用的HGML协议,实现无缝、透明地访问空间信息的各种资源。不同地理位置分布、不同管理平台、不同数据库存储、源于不同渠道、不同能力的资源,在分布式服务器群的支持配合下,数字地球平台可以将它们无缝、有机地集成在一起。同时,协调分散在不同地理位置的资源使用者,用户既可以使用单个资源及功能,还可以联合使用多个资源及合成功能。基于G/S模式的数字地球平台实现了分布式空间信息的资源汇集、充分共享。分布性是数字地球平台的最重要的特征之一。空间信息资源是由分布在不同地理位置、各类数据资源、信息资源、知识资源组成。正由于空间信息资源分布复杂、规模巨大,导致基于空间信息的各类计算无法实现集中式计算,因此,必然要采用分布式计算的形式。将以前B/S模式下服务器端的运算、分析放到G端来完成,解决了困扰空间信息B/S应用的网络瓶颈。数字地球平台的另一个特征是资源汇集、充分共享。空间信息的各种资源虽然是分布的,但通过数字地球平台可以实现任意用户(使用者)的有效提供和使用,不同地域、不同地点、不同平台、不同专有系统之间的充分共享。资源汇集、充分共享是数字地球平台的重要特征和最终目的,通过S端的分布式服务器群和HGML共享标准实现。根据G/S模式框架体系,搭建了UStar数字地球平台原型系统,并在数字旅游项目中进行了初步应用,取得了较好的效果。G/S模式的提出和初步的应用成果表明,该模式为空间信息在网络上的广泛应用提供了标准的、可行的技术体系架构,为未来空间信息技术的服务、管理、应用等提供了技术参考,是有意义的探索。更多还原

【Abstract】 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.更多还原