Of Webgis-internet Geographic Information System Research And Implementation,

Geographical Information System (CIS) is an information system which collects, stores, analyzes and visually expresses spatial data .WebGIS is hotspot and tendency of GIS. In traffic, travel and many other fields, WebGIS provids users dynamicly and visually geographical information.WebGIS is a multle-tier distributed system. This paper analyses the structure of WebGIS and the technology of Middleware. We present a three-tier WebGIS structure model based on middleware and used this structure model in the Dalian Traffic Information System, then we detailly describe the design and implementation of Data-Access Middleware and GIS ActiveX Control. it can be used for reference to implenment a WebGIS.According to new development of computer technology, this paper brings forward a SOAP-oriented structure and discusses interrelated problems.This paper also studyed a method to store spatial data into Oracle nested tables. This method provide a new scheme of spatial data management.