Design And Implementation Of Network Query System About Water Quality Data Of Three Gorges

GIS is a particular and important space information system, which collect, save, manage, analyze and describe the space and geography data of whole or parts of the earth. GIS is an information science and technology related with mankind's existence, development and progresses and valued by the people more and more. It will become the foundation of "digital Earth". Currently the technical development of GIS includes two aspects, on the one hand is according to the structure of Client/ Server, which use the data and the procedure on the server by customer's appropriative software; On the other hand is according to the structure of the Browser/ Server, which search various geography space data and carry on various geography space analysis by customer's general browser. To develop a WebGIS application system, the problem considered first is to use the ready-made WebGIS system platform or to develop GIS function module independently. Each of the two kinds of methods has the merits and shortcomings. The problem considered the next in order is the work mode of the system, such as: thin Client/fat Server, fat Client/thin Server. The requests of different work mode are different. The problem considered last is the storage of data, such as: all datas saving in files, all datas saving in database or parts of datas saving in files and parts of datas saving in database. The network query system about water quality data of Three Gorges is a WebGIS application system according to platform of ArcIMS and adopte the work mode of thin Client/fat Server. All the data managed by Oracle database, but the management of space data need the help of ArcSDE for Oracle.