Study On Progressive Transmission And Access Authority Management Of Object-Level Geospatial Data

With the rapid development of computer networks and the World Wide Web(WWW),providers and users of geospatial data can easily acquire,manage and share large amounts of geospatial data from the network.Network geographic information services are gradually becoming an integral part of people’s lives.But at the same time,there are also many serious problems.First,in the traditional geospatial information network transmission mode,when the client sends a request to the server and the server responds to return geospatial data,he user must wait until the data transfer is completed,and as the amount of data grows rapidly,the limited network bandwidth is increasingly unable to meet the geographic data transmission needs,users must wait a long time when downloading data sets from a remote server.Due to long waits,users may interrupt the transfer process,and the system cannot meet the "instant" principle of system response.Secondly,geographic information services have improved the openness and sharing of geographic information,this is also the case,it is very easy to copy and disseminate geospatial data through the Internet,which greatly increases the risk of geospatial data abuse and illegal dissemination,reliable technical means are needed to realize the security protection of geographic information services.Based on the analysis of the research status at home and abroad,this paper first proposes a more systematic and scientific measurement model for the object-level progressive selection of vector spatial data,based on this,the vector data progressive transmission framework is established by combining HTML5 technology;then considering the geographic data characteristics and the actual workflow of WebGIS,a network geographic information system authority management method is designed,and the object-level progressive selection strategy is applied to the vector geospatial data hierarchical encryption of rights management to secure geospatial data.The main research contents and innovations of this paper are as follows:(1)The current entropy-based map information metrics are summarized,and based on its deficiencies,a multi-level metric model of map information is proposed.(2)Based on the proposed map information metric model,the object-level progressive selection strategy of vector map is designed,and the progressive transfer mechanism of vector data based on HTML5 technology is studied.Experiments show that the progressive selection strategy and transmission mechanism proposed in this paper can effectively improve the response speed of the system,and also meet the visual perception effect of users.(3)According to the problems existing in the network geographic information system authority management model,a authority management model that takes into account the characteristics of geographic data and conforms to the actual application process is designed.Introducing the concept of dynamic rights to complete the authority allocation in spatial transaction cooperation.And the space scope under the jurisdiction of the department is used as the basis for the cooperation of authority allocation and transaction.At the same time,the vector data progressive selection strategy is applied in data hierarchical encryption to ensure data security.