ARCGIS工具箱TauDEM的介绍及相关操作

TerrainAnalysisUsingDigitalElevationModels(TauDEM)DavidTarboton1,DanWatson2,RobWallace,3KimSchreuders1,JeremyNeff11UtahWaterResearchLaboratory,UtahStateUniversity,Logan,Utah2ComputerScience,UtahStateUniversity,Logan,Utah3USArmyEngineerResearchandDevelopmentCenter,InformationTechnologyLab,Vicksburg,MississippiThisresearchwasfundedbytheUSArm[e-mail]Overviewofprinciplesandmethods(60min)Break(10min)HandsonusingArcGISandR(50min)Break(10min)TauDEMparallelmethods(15min)TauDEMonCSDMSBeach(20min)Discussionandoverruncushion(15min)1212345678Proportionflowingtoneighboringgridcell3is2/(1+2)Proportionflowingtoneighboringgridcell4is1/(1+2)•Pitremoval(standardfloodingapproach)•Flowdirectionsandslope–D8(standard)–D(Tarboton,1997,WRR33(2):309)–Flatrouting(GarbrechtandMartz,1997,JOH193:204)•Drainagearea(D8andD)•Networkandwatersheddelineation–Supportareathreshold/channelmaintenancecoefficient(Standard)–Combinedarea-slopethreshold(MontgomeryandDietrich,1992,Science,255:826)–Localcurvaturebased(usingPeukerandDouglas,1975,Comput.GraphicsImageProc.4:375)•Threshold/drainagedensityselectionbystreamdropanalysis(Tarbotonetal.,1991,Hyd.Proc.5(1):81)•OtherFunctions:DownslopeInfluence,UpslopeDependence,Wetnessindex,distancetostreams,Transportlimitedaccumulation•DevelopedasC++commandlineexecutablefunctions•MPICH2usedforparallelization(singleprogrammultipledata)•Reliesonothersoftwareforvisualization(ArcGISToolboxGUI)PrinciplesandmethodsFundamentalsofwatersheddelineationGeomorphologybasedchanneldelineation(objectivesupportthresholddetermination)D-InfinitymultipleflowdirectionmodelGeneralizedaccumulationfunctionalityPrinciplesandmethodsFundamentalsofwatersheddelineationGeomorphologybasedchanneldelineation(objectivesupportthresholddetermination)D-InfinitymultipleflowdirectionmodelGeneralizedaccumulationfunctionalityTopographydefineswatershedswhicharefundamentallythemostbasichydrologiclandscapeelements.Thestartingpoint:AGridDigitalElevationModelContours720700680740680700720740720720Agriddefinesgeographicspaceasameshofidentically-sizedsquarecells.Eachcellholdsanumericvaluethatmeasuresageographicattribute(likeelevation)forthatunitofspace.•Gridsizeisdefinedbyextent,spacingandnodatavalueinformation–Numberofrows,numberofcolumn–Cellsizes(XandY)–Top,left,bottomandrightcoordinates•Gridvalues–Real(floatingdecimalpoint)–Integer(mayhaveassociatedattributetable)TauDEMGridDataFormatAssumptionsInputandoutputgridsareuncompressedGeoTIFFMaximumsize4GB(~32,000x32,000rowsandcolsforsinglefileversion)ForlargerareasusemultifileversionGDALNodatatagpreferred(ifnotpresent,amissingvalueisassumed)Gridsaresquare(x=y)Gridshaveidenticalextents,cellsizeandspatialreferenceSpatialreferenceinformationisnotused(noprojectiononthefly)Theterrainflowinformationmodelforderivingchannels,watersheds,andflowrelatedterraininformation.RawDEMPitRemoval(Filling)FlowFieldChannels,Watersheds,FlowRelatedTerrainInformationThePitRemovalProblem•DEMcreationresultsinartificialpitsinthelandscape•Apitisasetofoneormorecellswhichhasnodownstreamcellsaroundit•Unlessthesepitsareremovedtheybecomesinksandisolateportionsofthewatershed•PitremovalisfirstthingdonewithaDEMIncreaseelevationtothepourpointelevationuntilthepitdrainstoaneighborPitFilling77677775779989999799111110111111119111112121012121212101212131210121313131113131410101114141412141415101010101515131515151010101016161416161511111111171714171715151515151818151818PitFilling7767777577998999979911111011111111911111212812121212101212131271213131311131314761114141412141415778915151315151588871616141616151111111117176171715151515151818151818PitsPourPointsOriginalDEMPitsFilled8074636967566052483045637218D8FlowDirectionModel-Directionofsteepestdescent45.0230486750.0305267Slope=Drop/DistanceSteepestdownslopedirectionGridNetwork1111111211111133311212515202Theareadrainingeachgridcellincludesthegridcellitself.1111111211111133311215222015ContributingArea(FlowAccumulation)1111111211111133311212515202FlowAccumulation10CellThreshold1111111211111133321522111520StreamNetworkfor10cellThresholdDrainageAreaStreamDefinitionWatershedDrainingtoOutletWatershedandStreamGridsDEMDelineatedCatchmentsandStreamNetworks•Foreverystreamsegment,thereisacorrespondingcatchment•Catchmentsareatessellationofthelandscape•BasedontheD8flowdirectionmodelEdgecontaminationEdgecontaminationarisesduetothepossibilitythatacontributingareavaluemaybeunderestimatedduetogridcellsoutsideofthedomainnotbeingcounted.Thisoccurswhendrainageisinwardsfromtheboundariesorareaswithnodatavalues.Thealgorithmrecognizesthisandreportsnodataresultinginstreaksofnodatavaluesextendinginwardsfromboundariesalongflowpathsthatenterthedomainataboundary.PrinciplesandmethodsFundamentalsofwatershed