Designand Implentation Of Agriculturalnon-point Source Pollution System Based On WeBGIS

In recent years,with the development of agriculture,the water environment problem whichcaused by agriculture non-point source(AGNPS) pollution on the global scale has been increasinglyprominent, meanwhlie becoming one of the important factors which restrict Chinese economic andsocial sustainable development. However, the present researches mostly stress on the non-pointsource pollution origin, the mechanism, the model and the control countermeasure and so on, but itlacks a good interactive user interface to present the management and the analysis of non-pointsource pollution. The appearance of WebGIS provides the possibility for the construction of theplatform, this paper uses RIA WebGIS technology to build the Poyang Lake agriculture non-pointsource pollution analysis platform which can be significant for many aspects like, preventing andcontrolling agriculture non-point source pollution, protecting the lake water environment,improving people’s quality of life and so on. It provides the basis for decision-making andevaluation which has grand potential value for marketing promoting.Taking Poyang Lake as an instance, this paper has established evaluation model of non-pointsource pollution based on GIS, multicriteria decision (technique for order preference by similarityto ideal solution), analyzed the trends of the development of WebGIS, developed with Silverlighttechnology on the WebGIS platform.Concrete research content is as follows:In the theoreticallevel,(1)Build the agriculture non-point source pollution indicator system of risk assessment inPoyang Lake;(2) Establish the evaluation model and integrate in the ArcGIS;(3)Expoundadvantages and disadvantages of ArcGIS Server,REST, Silverlight.In the technical level,(1)Definethe data struct,select the serialization and compression algorithm,design the way of GIS datatransmission which based on WebClient;(2)Use Geodatabase data model which integrates thespatial data and attribute data in SQL Server by adopting ArcSDE-spatial data engine;(3)Employthe idea of hierarchical design, the system can be top-down divided into different layers,maintaining high inside cohesion and low coupling;(4) Construct the agriculture non-point sourcepollution platform system based on WebGIS, which realizes the following functions: register forclients and convenient way to log in and out; basic map operation; prompt query for interspacedatabase; precision evaluation coefficient for subject map; counting and statistics of non-pointsource pollution instances; and comprehensive back-stage management, ect. Results from the development and practice show these conclusions:(1)This system has a goodexperience in the graphical display,users have a similar experience with desktop applications butdo not need to install a large package;(2)Compared to the transmission method of traditionalWebGIS system,this system only return zonaltable which rendering bythe client during collecting statistics of agriculture non-point source pollution information,thisdesign can be load-balanced to Broswer/Server architecture;(3)Through integrating on-linecalculation model on WebGIS, in scale of the country, analysising non-point sourcepollution,system shows that the area like Nanchang, Jinxian, Yugan, Xinjian, are in a high nitrogenloss potential risk, and the area which has middle-high nitrogen loss risk are mostly in the PoyangLake ring. It can provide a visual platform for decision makers in relevant departments, whichimproves the efficiency of agricultural NPS control work, and scientific decision-making.