Research On Geospatial Web Services And Microservices Technology Based On PDF Map

With the development of science and technology and social progress,geographic information service technology is booming.Didi Chuxing,Baidu Maps,Meituan and other geographic information applications are emerging in an endless stream,which promotes the generation of spatial data.People's daily life is increasingly dependent on spatial data,The era of spatial big data has arrived.With the continuous popularization and update of spatial data,various industries have put forward higher requirements for the production and application of map products in the field of surveying and mapping,and the demand for easy-to-use electronic map products has become urgent.Although the traditional digital line graphics(DLG)and Publication Originals of Map(POM)produced by China's map surveying and mapping department provide high-quality geographic information and spatial data,since the functions of photocopying and display were only considered in the past,these maps have the characteristics of large data volume and complex internal structure.And because it complies with the PDF format that is easy to distribute and print,there is currently no effective software solution for providing geographic information services based on PDF maps.These factors lead to a large amount of high-quality published original image data that can only be used for distribution and display at present.It is impossible to further develop more advanced geographic information services for other industries based on these high-quality data.In response to the above problems,based on the PDF map file structure,this article rewrites MuPDF,an open source PDF rendering component,to implement a PDF data parsing engine,expand the geographic information server GeoServer,and use the microservice framework SpringCloud,and finally design and implement a set of PDF map-based geographic information Web service and microservice system.This system can parse PDF maps,perform cropping,boundary recognition,format conversion,and other functions on the extracted vector data.It can also provide WMS services that conform to the OGC standard.Its advantage is to provide a complete modern geographic information service software solution for the PDF map produced by the surveying and mapping department in China.The main work of this article is as follows:(1)Designed and implemented a set of geographic information service software solutions based on PDF maps.(2)In-depth study of the structure of PDF documents and a thorough understanding of how information is stored in PDF maps.Research and compare the current open source PDF rendering library,select MuPDF library as the basis of the PDF parsing engine,study the source code of the MuPDF library,and expand its functions so that it can extract vector information stored in PDF maps.(3)On the basis of the foregoing work,a PDF data parsing engine is constructed to realize the structure of vector data.For the problem of too much data of the published original image,a clipping algorithm is designed and implemented for map vector data.For the published original image data organization form,Design and implement map boundary registration point recognition algorithm,realize further processing of map vector data,and lay a foundation for supporting geographic information services.(4)In-depth study of the open source geographic information service GeoServer and its GeoTools component for parsing map files.On the basis of understanding the source code,expand the data source of GeoTools and use the geographic information in the PDF map as the data source.The data source provides geographic information services.(5)Study the idea of microservices,learn the principles and use of the SpringCloud microservices framework,and package the PDF parsing engine into microservices.Tested the geographic information service software scheme based on PDF map,and tested the vector data extraction,cropping,boundary recognition and other functions of the PDF data parsing engine,as well as the web service and micro service functions provided finally.The experimental results show that the geographic information service software solution based on PDF map can accurately analyze the spatial data in PDF map and provide services,and the map surface effect is good,which meets the needs of actual scientific research projects in the field of surveying and mapping.