Study On Application Of WebGIS For Pavement

Recent years have witnessed the tremendous development of our country’highways which have achieved remarkable results.Highways have obviously geographical distribution characters,and to sufficiently realize paperless management on the rich supply of highway spatial data produced in the process of constructing,such as,route,bridge,tunnel,toll gate,we need to take advantage of the GIS(geographical information system).As newly developed GIS which combines information technology and geographical mapping technology,WebGIS is equipped with not only the convenience and accessibility of networking applications,but also the specialty of GIS which applies for the field where data is highly spatial in highway management.Traditional GIS is incapable of dealing with the material,like picture,audio,and is unable to meet the display demand of highway management in material.For this reason,based on the characters of GIS,combing the development condition and data management method of our country’ highway,and the apply condition of GIS used in highway system at home and abroad,this thesis determines research contents,meanings,and purposes.This thesis will build general WebGIS as development research platform by organically fusing ArcGIS,relevant WCF service,Silverlight,database.Based on this platform,this thesis will put forward storage measures which separated from spatial data and physically isolated from the aspects of map service data storage.After that,one character of the WebGIS,mutual query of spatial data,can be realized.Precise extraction on users’ search criteria by using geographical entity,particularly,from the aspects of text-based fuzzy geographical query,enhances the tolerance of search criteria.The defect that original control can only display text content would be remedied by means of overloading control so that the display of pictures’ attribute data can be realized.In terms of picture electronic records among transaction data,technologies like ends multiple queue buffer is applied to optimize the system performance.Furthermore,according to the phenomenon that program waits for users and the character that highway information points are spatially in one-dimension array,this thesis proposes two pre-fetch mechanisms-the “hotspot” data in server will be simultaneously pre-fetched after the client startup,and relevant data will be prefetched by forecasting the information point which might be accessed next time.Load timewhich can be perceived by most users would be eliminated by taking the mechanisms,and a series of data tests prove the validity of the mechanisms.At last,the clustering method is introduced in the aspects of identification of information points to make the identification easier and operation more concise.Highway pavement display system based on WebGIS,researched in this thesis,realizes space-attribute mutual query between spatial elements of highway pavement and relevant map service data to optimize related performance,to lay foundation for further vivid display of pavement display,to make exploration on the development mode in which WebGIS technology can be used in highway information system or other geographical information systems,and to provide guidance for access optimization under relevant circumstance by two prefetched mechanisms proposed before.