简介:Landresourcesarefacingcrisesofbeingmisused,especiallyforanintersectionareabetweentownandcountry,andlandcontrolhastobeenforced.Thispaperpresentsadevelopmentofdataminingmethodforlandcontrol.Avector-matchmethodfortheprerequisiteofdataminingi.e.,datacleaningisproposed,whichdealswithbothcharacterandnumericdataviavectorizingcharacter-stringandmatchingnumber.Aminimaldecisionalgorithmofroughsetisusedtodiscovertheknowledgehiddeninthedatawarehouse.Inordertomonitorlandusedynamicallyandaccurately,itissuggestedtosetupareal-timelandcontrolsystembasedonGPS,digitalphotogrammetryandonlinedatamining.Finally,themeansisappliedintheintersectionareabetweentownandcountryofWuhancity,andasetofknowledgeaboutlandcontrolisdiscovered.
简介:Ageo-referenceisaglobalorregionalgeographicalorgeodeticcoor-dinatesystemtowhichsensorsorspatialobjectdataarerelated.Hence,geo-ref-erencingisclosetothewellknownphotogrammetricconceptofexteriororabso-luteorientation,thecommonexecutionofwhichisindirect,viatheuseofgroundcontrolpoint.GPSandINStechnologieshavechangedthesituation,permittingdirectmeasurementofpositionandattitudeparametersandmakingexteriororien-tationfeasiblewithoutgroundcontrolatall,inprinciple.Theanalysisofaccuracyandreliabilityperformancediscloses,however,thatespeciallyINSdoesnotyetmeetthehighdemandsofphotogrammetry.Moreover,controlofsystematicer-rors,theproblemofdatumtransformation,andreliabilityconditionsmaketheuseofsomegroundcontrolpointsstillmandatory,atleastforanyhighperfor-mancegeo-referencing.
简介:ThispaperdiscussestheapproachesforautomaticalsearchingofcontrolpointsintheNOAAAVHRRimageonthebasisofdatarearrangementintheformoflatitudeandlongitudegrid.Thevegetationindextransformationandmulti-levelmatchingstrategieshavebeenproveneffectiveandsuccessfulastheexperimentsshowwhilethecontrolpointdatabaseisestablished.
简介:Accesscontrolinmulti-domainenvironmentsisoneoftheimportantquestionsofbuildingcoalitionbetweendomains.OnthebasisofRBACaccesscontrolmodel,theconceptsofroledelegationandrolemappingareproposed,whichsupportthethird-partyauthorization.Then,adistributedRBACmodelispresented.Finallytheimplementationissuesarediscussed.
简介:Basedonthearchitecturalsurveyprojectof“theChiLinNunneryRedevelopment'inHongKong,thispaperattemptstoinvestigatethetechniquesofbuilding3Ddigitaldocumentoflarge_scaletimberstructureandqualitycontrolduringconstructionbycomputer_based3Dsimulationforthewholeproject.Therewereseveralkeyissuesincludingprimarydataacquisition,3Dmodelinganddisplay,pre_assemblingthetotalbuildingandqualityexamination,etc.Inthispaper,someusefulexperiments,suchasthenewapplicationsofCCDdigitalcameras,imageandgraphprocessingsoftwarepackages(CAD,Photoshop,Photomodeler,Vexcel,etc.)tothearchitecturesarealsopresented.Thesemethodsintroducedinthispaperaresuitableforimageandgraphintegrateddatabasebuildingofcomplicatedarchitectures,andusefulforconvenientlymaintainingandreconstructingtheancientarchitectures.
简介:利用SPOT全色波段影像和LandsatETM+多光谱影像,采用波段特征分析法和改进的最佳波段指数法确定最佳融合波段。选择具有代表性的HSV变换、Brovey变换、PCA变换、Gram-schmidt变换和小波变换方法进行影像融合。针对融合后的影像采用定量评价法进行质量评价,通过不同地物的光谱、空间和纹理信息等进行比较分析构建适当的分类特征和规则,采用面向对象的遥感分类方法进行分类。结果表明,波段特征分析法和改进的最佳波段指数法结合,可以获得最佳融合波段。各融合方法均有效提升了影像效果,其中HSV和GS变换融合方法更好地保持了影像的多光谱和高分辨率特性,融合后各地物特征分类明显,可以有效应用于湿地分类;采用主成分分析法来设置面向对象分类中的波段权重,可以利用各波段信息量的差异进行影像的分割。基于各种遥感指数的面向对象分类方法用于湿地分类获得了93.62%的分类精度,与传统的分类方法相比有了很大进步,在湿地分类中具有很大的应用潜力。
简介:RTK(RealTimeKinematics)技术即实时载波相位差分技术,是实时处理两个测点载波相位观测量的差分方法,是一种高效的定位技术。载波相位差分方法分两类:一类是修正法,即将基准点的载波相位修正值直接发给流动站,改正流动站接收到的载波相位,然后求解流动站的实时坐标,该方法初始化速度慢,定位精度稍差,称准RTK技术;第二类是差分法,即求解起始相位整周模糊度,又称RTK初始化,然后再进行实时差分,是真正的RTK技术。差分法要求基准站GPS接受机实时地把观测数据及已知数据传输给流动站GPS接受机,流动站快速求解整周模糊度,在观测到5颗或以上卫星后,可实时求解出厘米级的流动站位置。由此可见,GPSRTK测量除应具备GPS信号接收系统外,还依赖两项关键技术:数据传输和数据实时处理技术。