The Design Of Vector Pyramid Structure

In recent years,with the development of the Internet and the information industry,big data has attracted more and more attention.And with the advent of the era of big data,geographic information has been more and more widely used in various fields and deeply affect people's lives.Especially the Web GIS developed faster and faster,which has penetrated into every aspect of our lives,Google maps,Baidu maps,for example.With the application of GIS more and more widely,the amount of GIS data has become more and more,which covers more and more information.Faced with the growing amount of data,GIS has a series of problems in the data display.The GIS data mainly include raster data and vector data.For raster data,the existing geographic information software has formed a mature pyramid mechanism.When loading and displaying the raster data,it will set up the corresponding Pyramid structure which can realize the rapid display in scaling and roaming.But there is no Pyramid mechanism for vector data,it is common to all the elements of a one-time load display when using it.So when the data is particularly large,there exists slow running speed and small scale elements overlap problems.According to this phenomenon,many scholars at home and abroad have put forward the corresponding solutions,including vector data block display,hierarchical display and so on.Especially with the development of network technology,the research on Web GIS vector slice and multi level vector data block storage is widely used.Based on the mature raster pyramid structure,this paper researched and explored the pyramid structure of vector data.and designed its structure.The corresponding method which could structure the vector data pyramid was also putted forward.The following work is done in this paper: Based on the principle of pyramid and the four fork tree principle,the Pyramid structure of vector data was studied and designed.Three problems were pointed out when structuring the vector pyramid: how to block data,how to process each layer of data,how to save vector data pyramid.The stratification process of vector data pyramid was studied,and the corresponding method was designed to realize this process.For data processing,based on the point,line and surface three different types of elements,different methods of data extraction were designed.For vector pyramid preservation,the linear four binary tree coding method was used to save the hierarchical results of the data.A corresponding index file was designed to store the elements to be displayed in each layer for thinning results of data.Finally,according to the vector data pyramid structure and the corresponding construction method,three kinds of data were selected and tested,which were point,line and surface.Hierarchical data results and data extraction results were analyzed and its effect was also demonstrated.