Digital Earth Three-Dimensional Spatial Information Services Research Of Key Technologies

With the explosive expansion of information resources, human put forward higher requirements in information collection, storage, management, analysis. In the settlement of population, resources, land, environment, disaster, planning, construction and other major issues, there are more and more research and application of vast amounts spatial information about multi-type, multi-scale, multi-temporal state, multi-dimensional. Expression of the traditional two-dimensional spatial information can no longer satisfy all aspects of these multi-level needs, therefore, in order to meet the needs of the unprecedented development of information industry, three-dimensional spatial information services research and application is imminent. System theory, information theory, control theory formation, computer technology, communication technology, satellite remote sensing and other spatial information technology, and Internet technology even have broaden prospect for scientific management of information resources.Digital Earth is a multi-resolution three-dimensional expression of the Earth, it can integrate GIS, RS, GPS, Internet, virtual reality and other high-tech, but also able to integrate vast amounts of geospatial data. Many countries are actively developing advanced spatial information technology such as remote sensing technology, geographic information systems technology and global positioning system technology, to achieve digital acquisition, processing, analysis of our human survival on Earth's natural and human aspects of spatial information, and based on this to address sustainable human survival and development of the many complex issues.With the rapid development of computer and Internet technology and wide application of information technology, three-dimensional space has become an increasingly widespread application requirement in our country. After years of accumulation and construction of three-dimensional spatial information technology research in China already have a base and developed a group of independent property rights in three-dimensional system software and application software, so that makes three-dimensional spatial information resources has been widely used in many industries. In achieving these results and research at the same time, three-dimensional spatial information management and application of technology has also encountered a number of new issues that must be resolved, specifically manifested as follows:(1) Three-dimensional format, a wide range of information, the information is stored in a large space. How to efficiently use the three-dimensional information has become a major problem, and making it difficult to manage the decision-making through data analysis and processing to obtain the results and information. With the development of various industrial applications and three-dimensional spatial data continues to increase, the accumulated information to create a variety of three-dimensional space can not be shared "information islands."(2) Three-dimensional information on the Internet when it is published, the transmission becomes another big problem. As the Internet bandwidth is limited, in order to release large amounts of data three-dimensional spatial information, the existing three-dimensional model can not guarantee fast and efficient operation. How to establish an efficient three-dimensional data model in order to quickly access and download the client, but also a technical problem.(3) Because of the confidentiality of data resources, it is impossible that all of the three-dimensional information centralized management; and the neglect of three-dimensional operation and distributed technology also makes the industry in dealing with mass distributed GIS three-dimensional spatial information distributed storage and processing of a serious shortage of investment in research. Research results achieved by the industrialization of a lack of effective channels to directly affect the three-dimensional network of home-made GIS software competitiveness.(4) Existing three-dimensional space on the Internet information service unable to meet all sectors of space information sharing needs. While the concept of wisdom of the earth, the wisdom of cites is put forward, it is urgent to integrate various types of spatial information resources to improve the three-dimensional spatial information services.For the above problems, three-dimensional space information network technology needed to introduce new technologies, ideas and systems to construct a three-dimensional space information network service system under the distributed environment. To achieve digital earth-based three-dimensional spatial information services, mainly including two aspects:Digital Earth technology and three-dimensional spatial information services technology. In this paper, "Digital Earth 3D spatial information services research of key technologies" can provide better research ideas for these issues.This paper studies three-dimensional digital earth technologies and information services, in the Eleventh Five-Year National "863" special issue "facing the three-dimensional network of information services technology research and software development" (2009AA12Z211) under the impetus of the project system, and to achieve three-dimensional space information sharing and service system based on the digital Earth. This paper studies three-dimensional spatial information services from the Digital Earth, under the development of Digital Earth's current situation and existing problems, Especially in the network environment, through the use of a variety of existing technology of Digital Earth three-dimensional space to share information in order to provide users with a more comprehensive three-dimensional GIS services;Based on Digital Earth in various industrial applications for spatial information services in urgent need of industrial applications, especially in three-dimensional spatial information service needs, this paper provide three-dimensional information services based on the key technology of Digital Earth as well as on the basis of this technology. And we also study the massive data sharing, three-dimensional space information service, service scheduling and many other key technologies. Ultimately, provide the early warning and services system in weather industry.This paper studies and discuss on Digital Earth-related systems and key technologies, launched three-dimensional spatial information services research based on Digital Earth. Extend MVE function and application mode, innovate technologies and products and address critical technical issues, based on the existing domestic large-scale GIS platform MapGIS Virtual Earth (MVE). Study and realize three-dimensional spatial data information service platform which has the capacity of three-dimensional spatial information massive storage, support its efficient transmission under distributed network environment, but also data analysis and processing. In particular, will be to undertake research in the following areas:(1) network model of the Earth 3DInternet 3D earth is the foundation to build the entire system. The platform system, the objective is to provide the public with map information search services to meet the people's daily travel needs, combining thematic information for the industry to deliver industry-information management and application services. Simply, it can be divided into server and client. Server is a three-dimensional model of the Earth's entire data storage and management; client-side is the Earth's model shows, including:client-side data communications, client is the Earth's model expression; it is including:client data communications, client data scheduling, data set management module and the client display module.(2) Massive storage and management of geographic informationThree-dimensional topography model is the main research contents of digital virtual space systems, and gradually developed into a three-dimensional GIS. Some three-dimensional GIS prototype system is put forward, but they only manage relatively simple data. In real applications, the vast amounts of geospatial data needs to be store and manage, and also need to address the large volume of spatial data fast real-time transmission, dynamic display and multi-source data management and efficient mass index.(3) Three-dimensional information modeling and visualizationWith the concepts such as "Digital Earth", "Digital City", "digital community" proposed, as well as spatial information and remote sensing data processing technology is developing rapidly, it will surely promote the traditional GIS services from two-dimensional to three-dimensional and network. Based on the three-dimensional network model of the Earth, the server transmits the dynamic three-dimensional real-time data to the client according to the client's request. The client receives the data sent from the server and maps three-dimensional visualization, and then three-dimensional graphics display on the computer screen, through the control of human-computer interaction in three-dimensional scene rendering, allowing users to roam in the realization of three-dimensional scene.(4) The mechanisms for efficient transport of three-dimensional spatial information and analysisLarge amount of information data three-dimensional space, there must be efficient transport mechanisms to ensure its rapid transmission. At the same time, transmission requires fault tolerance mechanisms to ensure their effective operation. This part studies compression and transmission and security of transmission, asynchronous call mechanisms, load balancing and fault tolerance mechanisms.(5) Three-dimensional network of spatial information servicesThe most important purpose of Web 3D spatial information is to provide a range of three-dimensional spatial information services, and can be able to provide services on the Internet, the real information sharing, cross-platform, distributed. Based on standard protocols, with an open, cross-platform, scalable, Node autonomy in distributed systems, Web services are the core and foundation. To facilitate the sharing and interoperability, cross-platform integration of geographic information, research OGC's Web services and XML specifications, proposed Geographic Information Web Service, GML (Geographic Markup Language). Spatial Web services use geographic information distributed in different nodes of the spatial data integration and data-binding function of spatial information services, to achieve Internet-based spatial information sharing technology. These tasks include:map visualization, spatial information retrieval, spatial analysis, maps, reports and so on. Spatial Geographic Information Web Services allows application developers to integrate GIS functionality into their Web applications without the need to build local capabilities.(6) Industry application software implementation and weatherThere are two modes in the implementation of three-dimensional spatial information network services:B/S mode and C/S mode. These two models in the data storage, release all use the same set of services, with versatility. We can combine these two modes stratification, including four levels:data management, GIS service layer, WEB service layer and presentation layer. Based on the system structure, according to Hubei weather warning application requirements, to achieve the industry on the meteorological examples are illustrated.Study Digital Earth and based on Digital Earth studies the standards and norms of three-dimensional information-sharing, and realize three-dimensional spatial information integration, organization and storage mechanism, therefore, establish the modules which have the capacity of three-dimensional spatial information services and integrations. High-speed Internet connection and integration of geographically distributed, heterogeneous high performance computer systems, processing tools and software systems and other resources as a whole, to achieve cross-boundary, the distribution of high-performance joint, multi-source, heterogeneous data integration and three-dimensional spatial information services, To provide users with an integrated high-performance computing services, spatial information, spatial information processing services and decision support services, to play the combined effectiveness of the network resources. The system can integrate and coordinate a variety of three-dimensional spatial information resources to provide multi-layered three-dimensional information services. The innovation of this paper is:(1) Improve its mass data storage mechanism, and improve the existing three-dimensional information model and the efficiency of three-dimensional data visualization, and provide massive dynamic three-dimensional data analysis services, based on MVE model,;(2) Study three-dimensional data space storage and transmission algorithms, improve storage efficiency, data transmission speed, improve the handling of three-dimensional data analysis model, based on service-oriented data model of three-dimensional space in the expression of efficient three-dimensional spatial data;(3) Study three-dimensional spatial information calculation mode, provide services of function of three-dimensional spatial information, complete Internet-based three-dimensional spatial analysis services which is user-specified(4) Relying on three-dimensional earth MVE model, Combining of images, vector, and three-dimensional model data, to achieve the deployment of distributed data, distributed service deployment, to compression and transmission, load balancing mechanisms such as a guarantee, to build a distributed network of three-dimensional data service system, and conducting studies in meteorology verification;...