基于网络资源获取铁路选线地理信息的方法与实现技术

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1、万方数据西南交通大学硕士研究生学位论文第lI页AbstractWiththedevelopmentofaerospaceremotesensingandnetworktechnology,aswellastherelaxationoflawsandpolicies，partsofsatelliteimagedataandDEMdatahasbeenopentothepublic，suchasLANDSATsatelliteseriesimages，EO一1satelliteimages，WMS(WebMapService)image

2、s，SRTMandASTERGDEMetc．Toapplythefreenetworksatelliteimagesandglobaldigitalelevationmodeltorailwaysurveyanddesigncanreducethefieldworkandimproveworkefficiencywithoutincreasingthecosts．Italsoprovidesareferencefortheaerialphotography．Thistechnologyandmethodswithobtainingi

3、mage，mosaic，reprojectionandcorrectionwillbediscussedinthispaper．Themainworkisasfollows：1)BycomprehensivecomparisonofLandsatseriessatelliteimages，EO-1satelliteimagery,WMSimagingandotherimagesfromtheaspectsofresolution，accuracy,obtainingtechnologyetc．andconsideringthecha

4、racteristicsoftherailwaylocation，WMSimageswerechoseasthemainstudyobjectinthispaper．2)TakeGoogleMapasanexample，analysisthewebpageofGMandgettheinformationoftheelementsonGMwebpage，therebylearnthenamedregularoftheURLofGMtilesandproposeditsconstructionmethod．3)BasedonCURL，t

5、heprogramwascamouflageasabrowsertoaccesstheserverandrealizethedownloadofGMtilesbymultithreadthroughhttpprotoc01．41InthecaseoftransformationfromWebMercatorcoordinatesystemtodecimaldegreesraster,amethodwasproposedtoinsteadthealgorithmnonlineartransformationbyalineartrans

6、formationandgivetheconditionsitcanbeapplied．Themethodiseasytorealizeandefficientandachievedgoodresultsinpracticaltests．5)Theprojectionmethodsofcommonlyusedcoordinatesystemsandconversionmethodsbetweencoordinatesystemsweresummarizedbasedonthedefinitionandcalculationmetho

7、dgivenbyEPSG(TheEuropeanPetroleumSurveyGroup)．6)Mosaicingtile，matchingofimageandterrain，reprojectionandSOonwererealizedbaseonGDAL(GeospatialDataAbstractionLibrary)．MultithreadtechnologywasappliedtomakefulluseofidlediskIOandsynchronousthewritingthreadbyWindowscriticalse

8、ctiontechnologyKeywords：WMS；TileImage；Download；ElevationModel万方数据西南交通大学硕士研究生学位论文第1lI页目录第1章绪论⋯⋯．．．⋯．．．．⋯．．．⋯．．．．．．．．．．