Designation:D5923−18StandardGuideforSelectionofKrigingMethodsinGeostatisticalSiteInvestigations1ThisstandardisissuedunderthefixeddesignationD5923;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONGeostatisticsisaframeworkfordataanalysis,estimation,andsimulationinmediawhosemeasurableattributesshowerraticspatialvariabilityyetalsopossessadegreeofspatialcontinuityimpartedbythenaturalandanthropogenicprocessesoperatingtherein.Thesoil,rock,andcontainedfluidsencounteredinenvironmentalorgeotechnicalsiteinvestigationspresentsuchfeatures,andtheirsampledattributesarethereforeamenabletogeostatisticaltreatment.Krigingmethodsaregeostatis-ticaltechniquesforspatialestimationbelongingtotheclassofleast-squaresestimators.Thisguidereviewscriteriaforselectingakrigingmethod,offeringdirectionbasedonaconsensusofviewswithoutrecommendingastandardpracticetofollowinallcases.1.Scope1.1Thisguidecoversrecommendationsforselectingappro-priatekrigingmethodsbasedonstudyobjectives,exploratorydataanalysis,andanalysisofspatialvariation.1.2Thisguideconsiderscommonlyusedformsofkriging,includingordinarykriging,simplekriging,lognormalkriging,universalkriging,andindicatorkriging.Multivariate,space-time,andotherless-frequentlyusedkrigingmethodsarenotdiscussed;however,thisisnotintendedtoreflectanyjudge-mentastothevalidityofthesemethods.1.3Thisguidedescribesconditionsforwhichkrigingmeth-odsarenotappropriateandforwhichgeostatisticalsimulationsapproachesshouldbeused.1.4Thisguidedoesnotdiscussnon-geostatisticalalterna-tivestokriging,suchassplinesorinverse-distancetechniques.1.5Thisguidedoesnotdiscussthebasicprinciplesofkriging.IntroductionstogeostatisticsandkrigingmaybefoundinnumeroustextsincludingRefs(1-3).2AreviewofkrigingmethodsisgiveninRef.(4).1.6Thisstandarddoesnotpurporttoaddressallofthesaf...
