Water Level Synchronous Display Technique Of Monitoring Sections Based On The WebGIS

With the development of water conservancy informazation, the non-engineering measurement for flood protection is becoming the trend of flood control and disaster reduction. The wireless communication technologies, remote sensing technologies and remote monitoring technologies have been widely used in building the system of hydrologic data collection and transmission for flood prevention. With the rapid development of Internet/ Intranet technology, the information system has been integrated and developed with network. The collection, storage, transmission, sharing and publishing of information technology provide new implementing and technical methods for flood prevention system .WebGIS is a kind of GIS, which based on the Internet, using the WWW protocol on client application software and running on the Internet. Web GIS, combining the web technology with GIS, is totally a new and revolutionary technology.Under this background, we can publish the real-time water level on the Internet with the visualization technology, and implement the function of water level monitoring and warning. In that case, the WebGIS can be quite important to flood control and disaster relieving.The thesis firstly introduced the characteristics, fundamental principle, structure model and calculating patterns of WebGIS, and then the features, architecture, operation mechanism and customization of the ArcIMS were disuissed.Next, it studies and explores the spring-based lightweight J2EE architecture and the structure of the WebGIS system.Based on the theory and related technologies above, using the pluggable components management mechanisms of lightweight J2EE framework and the characteristic of separation with infrastructure and business logic separation, we proposed the solution of water level real-time monitoring and warning, and researched the implementing of two key technologies: the water level information synchronous receiving and visualization information publishing.This solution took JfreeChart, an open source project, publishing technique for water level visualization on client. Using the Observer-Design-Patterns for reference, through the database trigger technique, we can realize the synchronous updating between the two kinds of data (the required data of water level visualization for publishing and the data of water level data acquisition system) with the event driven programming technique and the 'Push Model'.The prototype system, which based on the ArcIMS platform and lightweight J2EE framework, was made to achieve the real-time monitoring and early warning of the water level information on the monitoring points.