Research Of Hydrological Spatial-temporal Data Integration Method Based On Web Services

In some applications which have high requirements for real-time data,such as earlywarning system of flood disaster,hydrological datas change all the time.These datas arecrucial for the decision makers of decision-making center.This paper focuses on real-timehydrological datas of storing,organizing,publishing and integrated application.Geographic Information System (GIS) is a kind of technology which can be integratedinto various system framework. GIS enables capturing, storing, analyzing, and displayinggeographically referenced information. It allows us to view, understand, question, interpret,and visualize data in a way that is quickly understood and easily shared.On the other hand,Web services are base on open standards such as XML,SOAP,WSDL,UDDI.It is aarchitecture to achieve interoperablity between two applications. Now we have twoseparate technologies: GIS and Web services.And the point where they meet is ahydrological spatio-temporal data integration system where the GIS provides maps andobjects,and web services provide interface to access hydrologic time series data.In order to better reflect the characteristics of the hydrological spatio-temporal dara inthe design and implementation of Hydrological spatio-temporal data integrationsystem,this paper focuses on the ODM observed data storage model and WaterMLsemantic model.ODM data model is based on relational data model.It contains observeddatas, observatories,data source,observed variables,the time of observation, data collectionmethods, data quality and so on.The model mainly study the relations between these dataand the organizational structre.It can compensate for existing temporal data model whichcan not store hydrologic time series data.WaterML,as an XML structure language, defines the structure of all elements of the Webservice methods. One hand,it can be used to design structure of hydrological data class inthe development of of web service methods.The other hand,the caller of web services cancall the web service rightly and develop and maintain customer application which changeall the time easily because of WaterML.The paper build a hydrological spatial and temporal data integration system,which used GIS technology and regard.NET and ArcGIS Engine as development platform, andbased on Web services technology framework.This system integrates hydrologicalobservation time series data and spatial data,and achieve the fuction of displaying digitalmap,inquirying hydrological data, water level monitoring and early warning.