毕业论文外文翻译在遥感和地理信息系统的规模度量适用于毕业论文外文翻译中英文对照

毕业论文外文翻译--在遥感和地理信息系统的规模度量（适用于毕业论文外文翻译+中英文对照）外文资料与中文翻译MetricsofscaleinremotesensingandGISMichaelFGoodchild(NationalCenterforGeographicInformationandAnalysis,DepartmentofGeography,UniversityofCalifornia,SantaBarbara)ABSTRACT:Thetermscalehasmanymeanings,someofwhichsurvivethetransitionfromanalogtodigitalrepresentationsofinformationbetterthanothers.Specifically,theprimarymetricofscaleintraditionalcartography,therepresentativefraction,hasnowell-definedmeaningfordigitaldata.Spatialextentandspatialresolutionarebothmeaningfulfordigitaldata,andtheirratio,symbolizedasUS,isdimensionless.USappearsconfinedinpracticetoanarrowrange.TheimplicationsofthisobservationareexploredinthecontextofDigitalEarth,avisionforanintegratedgeographicinformationsystem.Itisshownthatdespitetheverylargedatavolumespotentiallyinvolved,DigitalEarthisneverthelesstechnicallyfeasiblewithtoday’stechnology.KEYWORDS:Scale,GeographicInformationSystem,RemoteSensing,SpatialResolutionINTRODUCTION:ScaleisaheavilyoverloadedterminEnglish,withabundantdefinitionsattributabletomanydifferentandoftenindependentroots,suchthatmeaningisstronglydependentoncontext.Itsmeaningsin“thescalesofjustice”or“scalesoveroneseyes”havelittleconnectiontoeachother,ortoitsmeaninginadiscussionofremotesensingandGIS.Butmeaningisoftenambiguouseveninthatlattercontext.Forexample,scaletoacartographermostlikelyrelatestotherepresentativefraction,orthescalingratiobetweentherealworldandamaprepresentationonaflat,two-dimensionalsurfacesuchaspaper,whereasscaletoanenvironmentalscientistlikelyrelateseithertospatialresolution(therepresentation’slevelofspatialdetail)ortospatialextent(therepresentation’sspatialcoverage).Asaresult,asimplephraselike“largescale”cansendquitethewrongmessagewhencommunitiesanddisciplinesinteract-toacartographeritimpliesfinedetail,whereastoanenvironmentalscientistitimpliescoarsedetail.Acomputerscientistmightsaythatinthisrespectthetwodisciplineswerenotinteroperable.InthispaperIexaminethecurrentmeaningsofscale,withparticularreferencetothedigitalworld,andthemetricsassociatedwitheachmeaning.Theconcernthroughoutiswithspatialmeanings,althoughtemporalandspectralmeaningsarealsoimportant.Isuggestthatcertainmetricssurvivethetransitiontodigitaltechnologybetterthanothers.Themainpurposeofthispaperistoproposeadimensionlessratiooftwosuchmetricsthatappearstohaveinterestingandusefulproperties.IshowhowthisratioisrelevanttoaspecificvisionforthefutureofgeographicinformationtechnologiestermedDigitalEarth.Finally,Idiscusshowscalemightbedefinedinwaysthatareaccessibletoamuchwiderrangeofusersthancartographersandenvironmentalscientists.FOURMEANINGSOFSCALELEVELOFSPATIALDETAILREPRESENTATIVEFRACTIONApapermapisananalogrepresentationofgeographicvariation,ratherthanadigitalrepresentation.AllfeaturesontheEarth’ssurfacearescaledusinganapproximatelyuniformratioknownastherepresentativefraction(itisimpossibletouseaperfectlyuniformratiobecauseofthecurvatureoftheEarth’ssurface).Thepoweroftherepresentativefractionstemsfromthemanydifferentpropertiesthatarerelatedtoitinmappingpractice.First,papermapsimposeaneffectivelimitonthepositionalaccuracyoffeatures,becauseofinstabilityinthematerialusedtomakemaps,limitedabilitytocontrolthelocationofthepenasthemapisdrawn,andmanyotherpracticalconsiderations.Becausepositionalaccuracyonthemapislimited,effectivepositionalaccuracyonthegroundisdeterminedbytherepresentativefraction.Atypical(andcomparativelygenerous)mapaccuracystandardis0.5mm,andthuspositionalaccuracyis0.5mmdividedbytherepresentativefraction(eg,12.5mforamapat1:25,000).Second,practicallimitsonthewidthsoflinesandthesizesofsymbolscreateasimilarlinkbetweenspatialresolutionandrepresentativefraction:itisdifficulttoshowfeaturesmuchlessthan0.5mmacrosswithadequateclarity.Finally,representativefractionservesasasurrogateforthefeaturesdepictedonmaps,inpartbecauseofthislimittospatialresolution,andinpartbecauseoftheformalspecificationsadoptedbymappingagencies,thatareinturnrelatedtospatialresolution.Insummary,representativefractioncharacterizesmanyimportantpropertiesofpapermaps.Inthedigitalworldthesemultipleassociationsarenotnecessarilylinked.Featurescanberepresentedaspointsorlines,sothephysicallimitationstotheminimumsizesofsymbolsthatarecharacteristicofpapermapsnolongerapply.Forexample,adatabasemaycontainsomefeaturesassociatedwith1:25,000mapspecifications,butnotall;andmayincluderepresentationsoffeaturessmallerthan12.5montheground.Positionalaccuracyisalsonolongernecessarilytiedtorepresentativefraction,sincepointscanbelocatedtoanyprecision,uptothelimitsimposedbyinternalrepresentationsofnumbers(eg,singleprecisionislimitedtoroughly7significantdigits,doubleprecisionto15).Thusthethreepropertiesthatwereconvenientlysummarizedbyrepresentativefraction-positionalaccuracy,spatialresolution,andfeaturecontent-arenowpotentiallyindependent.Unfortunatelythishasledtoacomplexsystemofconventionsinanefforttopreserverepresentativefractionasauniversaldefiningcharacteristicofdigitaldatabases.Whensuchdatabasesarecreateddirectlyfrompapermaps,bydigitizingorscanning,itispossibleforallthreepropertiestoremaincorrelated.Butinothercasestherepresentativefractioncitedforadigitaldatabaseistheoneimpliedbyitspositionalaccuracy(eg,adatabasehasrepresentativefraction1:12,000becauseitspositionalaccuracyis6m);andinothercasesitisthefeaturecontentorspatialresolutionthatdefinestheconventionalrepresentativefraction(eg,adatabasehasrepresentativefraction1:12,000becausefeaturesatleast6macrossareincluded).Moreover,theseconventionsaretypicallynotunderstoodbynoviceusers-thegeneralpublic,orchildren-whomayconsequentlybeveryconfusedbytheuseofafractiontocharacterizespatialdata,despiteitsfamiliaritytospecialists.SPATIALEXTENTThetermscaleisoftenusedtorefertotheextentorscopeofastudyorproject,andspatialextentisanobviousmetric.Itcanbedefinedinareameasure,butforthepurposesofthisdiscussionalengthmeasureispreferred,andthesymbolLwillbeused.Forasquareprojectareaitcanbesettothewidthofthearea,butforrectangularoroddlyshapedprojectareasthesquarerootofareaprovidesaconvenientmetric.Spatialextentdefinesthetotalamountofinformationrelevanttoaproject,whichriseswiththesquareofalengthmeasure.PROCESSSCALEThetermprocessrefersheretoacomputationalmodelorrepresentationofalandscape-modifyingprocess,suchaserosionorrunoff.Fromacomputationalperspective,aprocessisatransformationthattakesalandscapefromitsexistingstatetosomenewstate,andinthissenseprocessesareasubsetoftheentirerangeoftransformationsthatcanbeappliedtospatialdata.Defineaprocessasamappingb(x,)=(a(x,))whereaisavectorofinputfields,bisavectorofoutputfields,isafunction,tistime,islaterintimethan,andxdenoteslocation.Processesvaryaccordingtohowtheymodifythespatialcharacteristicsoftheirinputs,andthesearebestexpressedintermsofcontributionstothespatialspectrum.Forexample,someprocessesdetermineb(x,,)basedonlyontheinputsatthesamelocationa(x,),andthushaveminimaleffectonspatialspectra.Otherprocessesproduceoutputsthataresmootherthantheirinputs,throughprocessesofaveragingorconvolution,andthusactaslow-passfilters.Lesscommonly,processesproduceoutputsthataremoreruggedthantheirinputs,bysharpeningratherthansmoothinggradients,andthusactashigh-passfilters.Thescaleofaprocesscanbedefinedbyexaminingtheeffectsofspectralcomponentsonoutputs.Ifsomewavelengthsexistssuchthatcomponentswithwavelengthsshorterthanshavenegligibleinfluenceonoutputs,thentheprocessissaidtohaveascaleofs.ItfollowsthatifsislessthanthespatialresolutionSoftheinputdata,theprocesswillnotbeaccuratelymodeled.Whiletheseconclusionshavebeenexpressedintermsofspectra,itisalsopossibletointerpretthemintermsofvariogramsandcorrelograms.Alow-passfilterreducesvarianceovershortdistances,relativetovarianceoverlongdistances.Thustheshort-distancepartofthevariogramislowered,andtheshort-distancepartofthecorrelogramisincreased.Similarlyahigh-passfilterincreasesvarianceovershortdistancesrelativetovarianceoverlongdistances.L/SRATIOWhilescalingratiosmakesenseforanalogrepresentations,therepresentativefractionisclearlyproblematicfordigitalrepresentations.Butspatialresolutionandspatialextentbothappeartobemeaningfulinbothanaloganddigitalcontexts,despitetheproblemswithspatialresolutionforvectordata.BothSandLhavedimensionsoflength,sotheirratioisdimensionless.Dimensionlessratiosoftenplayafundamentalroleinscience(eg,theReynoldsnumberinhydrodynamics),soitispossiblethatL/Smightplayafundamentalroleingeographicinformationscience.InthissectionIexaminesomeinstancesoftheL/Sratio,andpossibleinterpretationsthatprovidesupportforthisspeculation.-Today’scomputingindustryseemstohavesettledonascreenstandardoforder1megapel,or1millionpictureelements.ThefirstPCshadmuchcoarserresolutions(eg,theCGAstandardoftheearly198Os),butimprovementsindisplaytechnologyledtoaseriesofmoreandmoredetailedstandards.Today,however,thereislittleevidenceofpressuretoimproveresolutionfurther,andtheindustryseemstobecontentwithanL/Sratiooforder103.Similarratioscharacterizethecurrentdigitalcameraindustry,althoughprofessionalsystemscanbefoundwithratiosashighas4,000.-Remotesensinginstrumentsusearangeofspatialresolutions,fromthe1mofIKONOStothe1kmofAVHRR.BecauseacompletecoverageoftheEarth’ssurfaceat1mrequiresontheorderof1015pixels,dataarecommonlyhandledinmoremanageabletiles,orapproximatelyrectangulararraysofcells.Foryears,LandsatTMimageryhasbeentiledinarraysofapproximately3,000cellsx3,000cells,foranL/Sratioof3,000.-ThevalueofSforapapermapisdeterminedbythetechnologyofmap-making,andtechniquesofsymbolization,andavalueof0.5mmisnotatypical.Amapsheet1macrossthusachievesanL/Sratioof2,000.-Finally,thehumaneye’sScanbedefinedasthesizeofaretinalcell,andthetypicaleyehasorder108retinalcells,implyinganL/Sratioof10,000.Interestingly,then,thescreenresolutionthatusersfindgenerallysatisfactorycorrespondsapproximatelytotheparametersofthehumanvisualsystem;itissomewhatlarger,butthecomputerscreentypicallyfillsonlyapartofthevisualfield.TheseexamplessuggestthatL/Sratiosofbetween103and104arefoundacrossawiderangeoftechnologiesandsettings,includingthehumaneye.Twoalternativeexplanationsimmediatelysuggestthemselves:thenarrowrangemaybetheresultoftechnologicalandeconomicconstraints,andthusmayexpandastechnologyadvancesandbecomescheaper;oritmaybeduetocognitiveconstraints,andthusislikelytopersistdespitetechnologicalchange.Thistensionbetweentechnological,economic,andcognitiveconstraintsiswellillustratedbythecaseofpapermaps,whichevolvedunderwhatfromtoday’sperspectivewereseveretechnologicalandeconomicconstraints.Forexample,therearelimitstothestabilityofpaperandtothekindsofmarkingsthatcanbemadebyhand-heldpens.Thecostsofprintingdropdramaticallywiththenumberofcopiesprinted,becauseofstrongeconomiesofscaleintheprintingprocess,somapsmustsatisfymanyuserstobeeconomicallyfeasible.Goodchild[2000]haselaboratedonthesearguments.Atthesametime,mapsservecognitivepurposes,andmustbedesignedtoconveyinformationaseffectivelyaspossible.Anyaspectofmapdesignandproductioncanthusbegiventwoalternativeinterpretations:one,thatitresultsfromtechnologicalandeconomicconstraints,andtheother,thatitresultsfromthesatisfactionofcognitiveobjectives.Iftheformeristrue,thenchangesintechnologymayleadtochangesindesignandproduction;butifthelatteristrue,changesintechnologymayhavenoimpact.ThepersistentnarrowrangeofL/Sfrompapermapstodigitaldatabasestothehumaneyesuggestsaninterestingspeculation:Thatcognitive,nottechnologicaloreconomicobjectives,confineL/Stothisrange.Fromthisperspective,L/Sratiosofmorethan104havenoadditionalcognitivevalue,whileL/Sratiosoflessthan103areperceivedastoocoarseformostpurposes.Ifthisspeculationistrue,itleadstosomeusefulandgeneralconclusionsaboutthedesignofgeographicinformationhandlingsystems.InthenextsectionIillustratethisbyexaminingtheconceptofDigitalEarth.Forsimplicity,thediscussioncentersonthelogtobase10oftheL/Sratio,denotedbylogL/S,andthespeculationthatitseffectiverangeisbetween3and4.ThisspeculationalsosuggestsasimpleexplanationforthefactthatscaleisusedtoreferbothtoLandtoSinenvironmentalscience,withouthopelesslyconfusingthelistener.Atfirstsightitseemscounter~ntuitivethatthesametermshouldbeusedfortwoindependentproperties.ButifthevalueoflogL/Siseffectivelyfixed,thenspatialresolutionandextentarestronglycorrelated:acoarsespatialresolutionimpliesalargeextent,andadetailedspatialresolutionimpliesasmallextent.Ifso,thenthesametermisabletosatisfybothneeds.THEVISIONOFDIGITALEARTHThetermDigitalEarthwascoinedin1992byU.S.VicePresidentAlGore[Gore,19921,butitwasinaspeechwrittenfordeliveryin1998thatGorefullyelaboratedtheconcept(www.d~~Pl9980131.html):“Imagine,forexample,ayoungchildgoingtoaDigitalEarthexhibitatalocalmuseum.Afterdonningaheadmounteddisplay,sheseesEarthasitappearsfromspace.Usingadataglove,shezoomsin,usinghigherandhigherlevelsofresolution,toseecontinents,thenregions,countries,cities,andfinallyindividualhouses,trees,andothernaturalandman-madeobjects.Havingfoundanareaoftheplanetsheisinterestedinexploring,shetakestheequivalentofa‘magiccarpetride’througha3-Dvisualizationoftheterrain.”ThisvisionofDigitalEarth(DE)isasophisticatedgraphicssystem,linkedtoacomprehensivedatabasecontainingrepresentationsofmanyclassesofphenomena.Itimpliesspecializedhardwareintheformofanimmersiveenvironment(ahead-mounteddisplay),withsoftwarecapableofrenderingtheEarth’ssurfaceathighspeed,andfromanyperspective.Itsspatialresolutionrangesdownto1morfiner.Onthefaceofit,then,thevisionsuggestsdatarequirementsandbandwidthsthatarewellbeyondtoday’scapabilities.Ifeachpixelofa1mresolutionrepresentationoftheEarth’ssurfacewasallocatedanaverageof1bytethenatotalof1Pbofstoragewouldberequired;storageofmultiplethemescouldpushthistotalmuchhigher.Inordertozoomsmoothlydownto1mitwouldbenecessarytostorethedatainaconsistentdatastructurethatcouldbeaccessedatmanylevelsofresolution.Manydatatypesarenotobviouslyrenderable(eg,health,demographic,andeconomicdata),suggestinganeedforextensiveresearchonvisualrepresentation.Thebandwidthrequirementsofthevisionareperhapsthemostdauntingproblem.Tosend1Pbofdataat1Mbpersecondwouldtakeroughlyahumanlifetime,andover12,000yearsat56Kbps.Suchrequirementsdwarfthoseofspeechandevenfull-motionvideo.ButthesecalculationsassumethattheDEuserwouldwanttoseetheentireEarthatImresolution.ThepreviousanalysisoflogL/Ssuggestedthatforcognitive(andpossiblytechnologicalandeconomic)reasonsuserrequirementsrarelystrayoutsidetherangeof3to4,whereasafullEarthat1mresolutionimpliesalogL/Sofapproximately7.AlogL/Sof3suggeststhatauserinterestedintheentireEarthwouldbesatisfiedwith10kmresolution;auserinterestedinCaliforniamightexpect1kmresolution;andauserinterestedinSantaBarbaraOnthisbasisthebandwidthrequirementsofDEbecomemuchmoremanageable.Assuminganaverageof1byteperpixel,amegapelimagerequiresorder107bpsifrefreshedoncepersecond.Everyone-unitreductioninlogL/Sresultsintwoordersofmagnitudereductioninbandwidthrequirements.ThusaTlconnectionseemssufficienttosupportDE,basedonreasonableexpectationsaboutcompression,andreasonablerefreshrates.OnthisbasisDEappearstobefeasiblewithtoday’scommunicationtechnology.CONCLUDINGCOMMENTSIhavearguedthatscalehasmanymeanings,onlysomeofwhicharewelldefinedfordigitaldata,andthereforeusefulinthedigitalworldinwhichweincreasinglyfindourselves.Thepracticeofestablishingconventionswhichallowthemeasuresofanearliertechnology-thepapermap-tosurviveinthedigitalworldisappropriateforspecialists,butislikelytomakeitimpossiblefornon-specialiststoidentifytheirneeds.Instead,Isuggestthattwomeasures,identifiedhereasthelargemeasureLandthesmallmeasureS,beusedtocharacterizethescalepropertiesofgeographicdata.Thevector-basedrepresentationsdonotsuggestsimplebasesfordefining5,becausetheirspatialresolutionsareeithervariableorarbitrary.Ontheotherhandspatialvariat;oninSmakesgoodsenseinmanysituations.Insocialapplications,itappearsthattheprocessesthatcharacterizehumanbehaviorarecapableofoperatingatdifferentscales,dependingonwhetherpeopleactintheintensivepedestrian-orientedspacesoftheinnercityortheextensivecar-orientedspacesofthesuburbs.Inenvironmentalapplications,variationinapparentspatialresolutionmaybealogicalsamplingresponsetoaphenomenonthatisknowntohavemorerapidvariationinsomeareasthanothers;fromageostatisticalperspectivethismightsuggestanon-stationaryvariogramorcorrelogram(forexamplesofnon-statjonarygeostatisticalanalysisseeAtkinson[2001]).Thismaybeonefactorinthespatialdistributionofweatherobservationnetworks(thoughothers,suchasunevenaccessibility,andunevenneedforinformationarealsoclearlyimportant).TheprimarypurposeofthispaperhasbeentoofferaspeculationonthesignificanceofthedimensionlessratioL/S.Theratioisthemajordeterminantofdatavolume,andconsequentlyprocessingspeed,indigitalsystems.Italsohascognitivesignificancebecauseitcanbedefinedforthehumanvisualsystem.IsuggestthattherearefewreasonsinpracticewhylogL/Sshouldfalloutsidetherange3-4,andthatthisprovidesanimportantbasisfordesigningsystemsforhandlinggeographicdata.DigitalEarthwasintroducedasonesuchsystem.AconstrainedratioalsoimpliesthatLandSarestronglycorrelatedinpractice,assuggestedbythecommonuseofthesametermscaletorefertoboth.ACKNOWLEDGMENTTheAlexandriaDigitalLibraryanditsAlexandriaDigitalEarthPrototype,thesourceofmuchoftheinspirationforthispaper,aresupportedbytheU.S.NationalScienceFoundation.REFERENCESAtkinson,P.M.,2001.Geographicalinformationscience:Geocomputationandnonstationarity.ProgressinPhysicalGeography25(l):111-122.Goodchild,MF2000Communicatinggeographicinformationinadigitalage.AnnalsoftheAssociationofAmericanGeographers90(2):344-355.Goodchild,M.F.&J.Proctor,1997.Scaleinadigitalgeographicworld.GeographicalandEnvironmentalModellingl(1):5-23.Gore,A.,1992.EarthintheBalance:EcologyandtheHumanSpirit.HoughtonMifflin,Boston,407~~.Lam,N-S&D.Quattrochi,1992.Ontheissuesofscale,resolution,andfractalanalysisinthemappingsciences.ProfessionalGeographer44(l):88-98.QuattrochiD.A&M.F.Goodchild(Eds),1997.ScaleinRemoteSensingandGIS.LewisPublishers,BocaRaton,406~~.

中文翻译：在遥感和地理信息系统的规模度量迈克尔·F古德柴尔德

（美国国家地理信息和分析中心，加州大学圣巴巴拉分校地理系）摘要：长期的规模有多种含义，其中一些生存了从模拟到数字表示的信息比别人更好的过渡。具体来说，在传统的制图，代表分数，度量规模的主要有数字数据没有定义的含义。空间范围和空间分辨率都是有意义的数字数据，和他们比，作为美国的象征，是无量纲的。在实践中一个狭窄的范围似乎只限于美国。这个观察的影响，探讨在“数字地球”的背景下，为一体的综合地理信息系统的设想。据显示，尽管可能涉及非常大的数据量，数字地球不过是技术上今天的技术是可行的。关键词：规模地理信息系统遥感空间分辨率

引言：规模是在英语长期负荷过重，由于许多不同的和经常独立根丰富的定义，这样的含义是强烈依赖于上下文。它的意义在“正义的尺度”或“的眼睛，尺度”连接到对方，或者其在遥感和地理信息系统的讨论意义不大。但意义往往是含糊不清，甚至在这后一种情况下。例如到制图，规模最有可能涉及到代表的比例，或在一个平面，二维，如纸张表面之间真正的世界地图表示的缩放比例，而环境科学家的规模可能涉及到空间决议（代表性的空间细节的水平）或空间范围（代表性的空间覆盖）。因此，像“大规模”的一句简单的话，可以发送错误消息时，社区和学科互动-一个制图它意味着精致的细节，而环境科学家，这意味着粗细节。计算机科学家可能会说，在这方面，这两个学科是不能互通。

可以在文献中找到许多规模的全面审查。

在本文中，我特别提到的数字世界的含义规模，并与每个意义的指标。关注的是整个空间的意义，虽然时间和光谱的意义也很重要。我认为某些指标生存过渡到数字技术比别人更好。

本文的主要目的是提出了这样两个指标的无量纲的比例，似乎有有趣和有用的属性。我告诉这个比例是如何被称为数字地球的地理信息技术的未来的一个特定的视觉有关。最后，我将讨论如何可能的方式都可以访问的用户更广泛的范围比制图和环境科学家定义的规模。

四种含义的规模水平空间详细

代表分数

纸质地图是地理变异的模拟表示，而不是一个数字表示。地球表面上所有的功能都使用大约为代表的部分（因为地球表面的曲率，这是不可能使用一个完全统一的比率）的统一比例缩放。代表分数的权力源于映射的做法是在它的许多不同的特性。首先，纸质地图的功能定位精度对一个有效的限制，因为不稳定的材料用来做地图，有限的能力来控制笔的位置，绘制地图，和许多其他实际的考虑。因为在地图上的定位精度是有限的，有效的地面上的定位精度取决于所代表的分数。一个典型的（和比较大方）地图精度标准是0.5毫米，定位精度为0.5毫米，除以代表部分（例如，在1:25000的地图为12.5米）。第二，线条和符号的大小宽度的实际限制，创建一个类似的链接：之间的空间分辨率和代表性的部分，它是难以显示功能远远超过0.5毫米，对面有足够的清晰度。最后，代表分数作为替代在地图上描绘的功能，因为这个空间分辨率的限制，部分是因为测绘机构，在打开相关的空间分辨率是通过正式的规格。总之，代表分数的特点纸质地图的许多重要特性。

在数字世界中，这些多个协会没有必然的联系。特性可以表示为点，线，所以符号特征的纸质地图不再适用的最小尺寸的物理限制。例如，一个数据库可能包含与1:25,000地图的规格相关的一些功能，但并不是所有的，并可能包括超过12.5米的地面较小的特点交涉。定位精度也不再一定依赖代表性的部分，因为点可以位于任何精密，内部的数字表示所施加的限制（如，单精度被限制在大约7个显着的数字，双精度为15）。因此，现在的三个属性，方便代表分数-定位精度，空间分辨率和功能的内容，总结-潜在的独立。

不幸的是，这已经导致了公约的复杂系统，在努力维护代表分数作为一个普遍的定义数字数据库的特点。当创建数据库直接从纸质地图，通过数字化或扫描，它是所有三个属性，以保持相关。但在其他情况下代表分数列举的数字化数据库是一个暗示其定位精度（例如，一个数据库有代表性的分数1：12000，因为其定位精度为6米）;和在其他情况下，它是功能的内容或空间分辨率，定义了传统的代表分数（例如，数据库中有代表性的部分1:12,000因为包括至少6米跨功能）。此外，通常无法理解这些公约的新手用户-广大市民，或儿童-他们可能会因此被分数来表征空间数据的使用非常混淆，尽管其熟悉的专家。

空间范围

长期的规模往往用来指研究或项目的范围或程度，空间范围是一个明显的度量。它可以被定义在区域措施，但长度为这次讨论的目的是首选措施，以及将使用符号L。一平方米的项目区，它可以设置到区域的宽度，但为长方形或形状奇特的项目区面积的平方根提供了一个方便的度量。空间范围定义的一个项目，它的长度测量的平方上升的相关信息总量。

生产规模

长期的过程，这里指的计算模型或景观修改过程中的代表性，如糜烂或径流。从计算的角度来看，这个过程是一个改造景观，需要从现有的状态，一些新的状态，在这个意义上说的过程，可以应用到空间数据的转换的整个范围的一个子集。映射定义为b(x,)=(a(x,))，其中a是输入字段的载体，b是一个输出域的载体，是一个函数，t是时间，就是后来的时间比，x表示位置。进程有所不同，根据他们如何修改其输入的空间特征，这些都是最好的空间谱的贡献表示。例如，一些进程确定b(x,)只在同一地点的投入的基础（x，），因此有空间谱的影响最小。其他进程产生比其流畅的输入输出，通过平均或卷积过程，因此，作为低通滤波器。不太常用，工艺生产的产出比投入更为坚固，锐化，而不是平滑梯度，因此，作为高通滤波器。规模可以定义一个过程，通过检查输出频谱成分的影响。如果某些波长s存在与波长比S短对产出的影响可以忽略不计，这样组件，那么这个过程是说拥有的规模。因此，如果s是比输入数据空间的决议S少，进程将不能准确建模。虽然这些结论已在光谱方面表示，它也可以解释变异函数和相关图。一个低通滤波器，减少短距离，相对长距离的方差方差。从而降低短距离的变差，增加短距离的相关图的一部分。同样，一个高通滤波器增加的方差相对短距离到长距离的方差。

L/S比值

虽然缩放比例使感模拟申述，代表分数是明确的数字表示的问题。但是，空间分辨率和空间范围都出现在模拟和数字两种情况是有意义的，尽管与矢量数据的空间分辨率的问题，。两个砂L有长度的尺寸，所以他们的比例是无量纲。无量纲的比值往往发挥在科学的基础性作用（例如，在流体力学中的雷诺数），因此它是可能的L/S可能在地理信息科学的基础性作用。在本节中，我考察了一些L/S比值的实例，并提供支持这种推测可能的解释。

-今天的计算机行业似乎已经落户为了1megapel，或100万像素的屏幕标准。第一的电脑有很多粗糙的决议（例如，早期的80年代海巡署标准），但在显示技术的改进，导致了一系列的更多和更详细的标准。然而，今天，很少有证据的压力，进一步提高分辨率，业界似乎是为了103L/S比值的内容。类似的比率特征，目前数码相机行业，虽然专业系统可以发现高达4000的高比率。

-遥感仪器使用范围，空间分辨率从1米的IKONOS卫星AVHRR的1公里。因为需要1015像素的顺序完全覆盖了地球表面1米处，数据通常处理更易于管理的瓷砖，约矩形阵列或细胞。多年来，TM影像已被平铺在约3000细胞×3,000细胞阵列，为3000L/S比值。

-S的纸质地图的价值取决于地图制作技术，技术的象征，和一个0.5毫米的价值是不是非典型。一个跨图幅1米，从而达到一个L/S的2000比。

-最后，人眼的S可以定义为视网膜细胞的大小，并具有典型的眼睛为了108的视网膜细胞，意味着一个L/S比率10000。然后，有趣的是，屏幕的分辨率，用户发现普遍感到满意大约相当于人类视觉系统的参数，它是有点大，但在计算机屏幕上通常只填充的视野。

这些例子表明，在103和104之间的L/S比值是全面的技术和设置的范围很广，包括人眼发现。两个不同的解释，立即自己的建议：窄幅震荡可能是技术和经济拮据的结果，从而可能扩大随着技术的进步，变得便宜;也可能是由于认知能力的限制，因此很可能仍然存在，尽管技术变革。纸质地图，从今天的角度来看，什么是严重的技术和经济上的限制下发展的情况很好地说明了这种技术，经济和认知的限制之间的紧张。例如，有稳定