Henan Zhaokou Irrigation Management System Based On WebGIS

Irrigation informatization is an irreversible trend. According to the data of Zhaokou irrigation, this paper analyzes the business of irrigation management and brings WebGIS technology in the system in order to improve the effective of management of this irrigation, which is imperative in decision-making process.There are4parts in this paper:l)According to the research status and basic information of Zhaokou irrigation, this paper designs a RIA system based on WebGIS. With the advantages of Flex Viewer, the system can develop the irrigative models independly to solve the update problem. Due to the dual merits both of the C/S and B/S, it is easy and efficient to achieve the data management with better users’interface.2)With ArcGIS Server&SQL2005technologies, the database is divided into two parts, the spatial database and the attribute database. Remote Facade pattern and the DTO/VO model are used to solve the problems of data communication and status consistency, and these problems are produced in the development process because of the system’s heterogeneous and distributed structure. This system accomplishes a great many of basic functions such as map display, information query, data editing, data statistics, and the irrigative models.3)According to the crop water requirement phases and the schedule of standard irrigation, this paper defines the irrigative stage range to analyze the precipitation trend and the water demand in the long term. Based on the stages, the ISODATA model is used to calculate the trend of the precipitation using the factors of the precipitations of the stages aimed to determine the status of the trend in dry and wet standard. After the step, the Markov state transition matrix forecasts the status of the irrigative stages, and the eigenvalues are used to calculate the values of the precipitation of the stages. The forecast results have bean verified, and the results use status range instead of the exact value, which can provide many solutions for decision maker to choose.4) Using the penman-monteith formula and the correction of crops coefficient, this system implements the model of calculation of ETC.RS technology is used to inverse the soil moisture in each irrigative stages divided in the paper in order to generate the thematic map of soil moisture. According to the precipitation forecast results, the water demand results and the soil moisture distribution information, this system uses the GIS model to export the crop water requirement thematic maps in order to accomplish the irrigative model. Using the Geoprocessing Service server, this model is integrated to the Zhaokou irrigation management system which provides a theoretical basis for Zhaokou irrigation water allocation decisions.