地统计内插方法 克里金插值(Kriging).ppt

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1、标题Chap8.SpatialStatisticsinGISGeographicInformationSystem标题8.1Introduction8.2RandomField8.3SimpleKrigingGeographicInformationSystem8.1IntroductionLowvarianceHighvarianceSpatialheterogeneity/variabilityToanswervariousestimationproblemssuchas•Whataretheelevationvaluesinanunmeasuredlo

2、cation?•Howtoinferelevationvaluesfromothermeasurementsinthesameandotherlocations?WhenisGeostatisticsneeded?8.1IntroductionWhenisGeostatisticsneeded?Howtoconstructhigh-resolutionDEMthatareconsistentwithdataofvarioustypesandscales?•Wheretolocatethenextobservationpoints?Howmanytolocat

3、e?8.1IntroductionReviewofProbability•Frequencytablerecordshowoften(intermsofpercentage)observedvaluesfallwithincertainintervalsorclasses.•Histogram:graphicalrepresentationoffrequencytable.–Commontouseaconstantclasswidth–Theheightofeachbarcorrespondstothefrequency•Cumulativefrequenc

4、ytableandhistogram-recordthetotalnumberofvaluesbelowcertaincutoffs.8.1Introduction8.1IntroductionProbabilitydensityfunction(PDF):p(u)–DiscretePDF:assignsaprobabilitytoeacheventTheoutcomeofflippingacoin•ThenumberofroadinanareaContinuousPDF:determinestheprobabilitythataneventfallswit

5、hinacertainrange•Theelevationinanarea8.1IntroductionSomecommonsummarystatistics:–Measurementsoflocation:mean,median–Measurementsofspread:variance,standarddeviation,coefficientofvariation–Measurementsofshape:coefficientofskewness8.1Introduction8.1Introduction8.1Introduction8.1Introd

6、uction8.1Introduction8.1Introduction8.2RandomFieldArandomvariable(stochasticvariable)isdefinedbyasetofpossiblevalues(thesamplespace)andaprobabilitydistributionoverthisset.Arandomfunction,U(x),isanindexedcollectionofrandomvariables.Alsocalledrandomfieldorstochasticprocess.–k(x)asper

7、meabilityalongarandomlypackedsandcolumn–z(x)aselevationinanareaAsamplefunctionorrealizationofarandomfield:oneparticulartrialorexperimentoutofmany;TheensembleoftherandomfieldElevation/mx/km8.2RandomFieldN-pointCDF&PDFThestatisticalpropertiesofarandomfieldarecompletelydefinedwithallt

8、hemultivariate(n-point)PDF