基于开源Web-GIS的县域土壤信息系统设计

Design of county-level soil information system based on Web-GIS

土壤学研究和社会生产实践所积累的大量土壤数据,是生产实践和科学研究的宝贵基础性资料,迫切需要依靠信息技术加强土壤信息的管理和应用。但县域尺度土壤信息系统的构建面临着成本高企、维护困难和性能瓶颈等诸多问题。针对以上问题,该文应用低成本的开源Web GIS平台MapGuide Open Source,以吉林省梨树县为研究区,基于第二次土壤普查数据库和《梨树土壤志》等数据,在Visual Studio.Net环境下设计开发了县域土壤信息系统。该系统设计为一个3层架构的Server/Brower开放应用系统,可通过Internet浏览器访问,增强了土壤信息的共享性;系统浏览器端采用了Fusion灵活网页布局方案,具有良好的灵活性、扩展性和响应速度;系统实现了地图导航、地图服务、要素服务和专题图功能,为县域土壤资源和其他相关地学背景资料的查询和展示提供了方便;系统建立了与Google WMS的动态联系,方便切换底图,扩展了系统的可视化效果。系统后台管理集中在一个管理客户端,使得后期系统维护和升级较为便利。运行结果表明,该系统在开发维护成本和性能上达到了一个较好的均衡,为后续应用系统的进一步扩展奠定了基础。

Science research and production practice have accumulated a large number of soil data, which is the valuable essential data for practice and research. It is significant for sustainable land use to enhance soil information management and sharing. But currently the construction of county level soil information system is facing many issues such as the high cost, difficult to maintain, and performance bottlenecks, etc. In this paper, a low-cost open-source Web GIS platform （MapGuide Open Source） was adopted to design and develop a county-level soil information system （CLSIS） for Lishu county based on the second soil survey database and other soil data in Visual Studio.Net. The system development was divided into four stages：system requirement analysis, system design, system implementation and system testing. The system was designed as a three-tier Server/Brower open application system. Client tier may be a browser terminal or a management terminal. Web tier, deployed on the internet information server, was responsible for receiving requests from browsers, passing the requests to the application server and returning the response to browsers. Application tier was composed of a GIS server （MapGuide Open Source 2.1）, a database server and a remote Web Map Service （WMS） component. The database was organized as the attribute database and spatial database, respectively. The attribute database includes the soil basic information table, soil physical properties table, soil chemical properties table, geomorphology table, and land use and administrative table. Among all spatial data, the soil, topography, land use and administrative maps are vector layers, but the precipitation and temperature are stored as raster format. The server-side of CLSIS provided map services, feature services, render services and image services. The functions of server-side were implemented by C# and MapGuide Server API in Visual Studio.Net. The browser-side programming is applied with fusion flexible page layout solution, which has better flexibility, scalability and response speed. Fusion framework is an expanded JavaScript library derived from OpenLayers and JXLib. The system built up a dynamic contact with Google WMS, facilitating the switch of base map among the standard, satellite, hybrid and terrain. Google WMS enhanced the visual effect and intuitive feelings of CLSIS. The system maintenance and management is mainly done by MapGuide Maestro, which is a client software based on Client/Server structure. The centralized management makes system maintenance and upgrades more convenient. CLSIS realizes the map navigation, map services, feature services and thematic mapping functions. By utilizing these functions mentioned above, users can conveniently query and browse soil resources and other relevant geographic background informations for Lishu county. The available soil data include soil type, soil texture, soil parent materials, soil organic matter, the thickness of humus, pH value, total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus, available potassium, trace elements and soil water retention, etc. The operation result shows that the system reaches a good balance between cost of development/maintenance and performance. This system will be a basic county level soil information platform for further expansion in the application of multiple fields.