简介:IthaslongbeenacknowledgedthatGISdatacanbeusedasauxiliaryinformationtoimproveremotesensingimageclassification.Inpreviousstudies,GISdatawereoftenusedintrainingareaselectionandpostprocessingofclassificationresultoractedasadditionalbands.Generally,itisfulfilledinastatisticalorinteractivemanner,soitisdifficulttousetheauxiliarydataautomaticallyandintelligently. Furthermore,iftheclassifierrequestscertainstatisticalcharacteristics,theadditionalbandmethodcannotbeusedbecausemostauxiliarydatadonotmeettherequirementsofstatisticalcharacteristics.Ontheotherhand,expertsystemtechniqueswereincorporatedinremotesensingimageclassificationtomakeuseofdomainknowledgeandlogicalreasoning.Butbuildinganimageclassificationexpertsystemwasverydifficultbecauseofthe“knowledgeacquisitionbottleneck”. Spatialdataminingandknowledgediscovery(SDMKD),istheextractionofimplicit,interestingspatialornon_spatialpatternsandgeneralcharacteristics.Weproposedatheoreticalandtechnicalframeworkofspatialdataminingandknowledgediscovery(Lietal.,1997).Andspatialdataminingissupposedtobeusedintwoaspects,oneisintelligentanalysisofGISdata,theotheristosupportknowledgedriveninterpretationandanalysisofremotesensingimages.SDMKDprovidesanewwayofknowledgeacquisitionforremotesensingimageclassification.Severalresearchershavedonesomeworkinthisfield.Eklundetal.(1998)extractedknowledgefromTMimagesandgeographicdatainsoilsalinityanalysisusinginductivelearningalgorithmC4.5.Huangetal.(1997)extractedknowledgefromGISdataandSPOTmultispectralimageinwetlandclassificationusingC4.5too.Inthesetwostudies,geographicdatawereconvertedfromvectortorasterformatinwhichthesamplingsizeisequaltoimagepixelsize.Theimplementationofdataminingtechniquesinspatialdatabase,especiallyinductivelearningmethod,andthecombinationo
简介:ThispaperdiscussestheplacementofChineseannotationfrompointofviewofgraphics.AreaFeatureisclassifiedassimplepolygon,complexpolygonandspecialpolygon.Forsimpleones,annotationsareplacedalongthelongestedge.Forcomplexones,firstlythepolygonaresimplifiedaccordingtoclosepoints,thenthelongestdiagonalisgottenbycomparinglength,lastly,annotationsareplacedalonglong-diagonal.Forspecialones,thepolygonarepartitionedintoseveralpartsbyacertainruleforgettingtheirsub-diagonals,thentheirannotationareplacedbymeansofthesecond.
简介:Theestuaryandcoastisanareawherethelandandtheseainteractandaplaceinwhichhumanbeingsfrequentlymoveaboutsothatunderstandingandcontrollingthechangeanddevelopmentmodesofthecoastallandformplaysavitalpartinexploitingandprotectingcoastalresources.Amodelisthegeneralizationandabstractionofobjectivethings.Thispapersummarizesfourmethodsforthelandformdevelopmentofthetidalshoreandunderwaterdelta,mainlydiscussesthemodel'sstructuralelements,andpresentstheirspecificapplicationonthebasisoftheauthors'casestudy.Withtheapplicationoftheprofilemodel,thedynamicchangeofcoastallandformcanbeclearlyseenbycontrastingthedifferentprofilesofdifferentyears.Throughtheshrinking,expandingandtransformationoftheisobath,planemodelisusedtostudythemacro-changeoftheshoalandthecoastallandform.Speedmodelisanefficientmeanstoanalyzethetrendoferosionanddepositionandthelocalchangeinagreatareaofthesea.Statisticalsurveymodelisastaticanalysis,whichcanbeusedtoestablishtherelationshipbetweentheerosionanddepositionoftheshoalandthealtitudeandslopeofsurveyspot.
简介:Theobjectivesofthisstudyaretoassesslandsuitabilityandtopredictthespatialandtemporalchangesinlandusetypes(LUTs)byusingGIS-basedlandusemanagementdecisionsupportsystem.AGISdatabasewithdataonclimate,topography,soilcharacteristic,irrigationcondition,fertilizerapplication,andspecialsocioeconomicactivitieshasbeendevelopedandusedfortheevaluationoflandproductivityfordifferentcropsbyintegratingwithacropgrowthmodel--theerosionproductivityimpactcalculator(EPIC).Internationalfoodpolicysimulationmodel(IFPSIM)isalsoembeddedintoGISforthepredictionsofhowcropdemandsandcropmarketpriceswillchangeunderalternativepolicyscenarios.Aninferenceengine(IE)includinglandusechoicemodelisdevelopedtoillustratelandusechoicebehaviorbasedonlogitmodels,whichallowstoanalyzehowdiversifiedfactorsrangingfromclimatechanges,croppricechangestolandmanagementchangescanaffectthedistributionofagriculturallanduse.Atestforintegratedsimulationistakenineach0.1°by0.1°gridcelltopredictthechangeofagriculturallandusetypesatgloballevel.Globallandusechangesaresimulatedfrom1992to2050.
简介:Thehorizontalaccuracyoftopographicdatarepresentedbydigitalelevationmodel(DEM)resolutionbringsaboutuncertaintiesinlandscapeprocessmodelingwithrasterGIS.Thispaperpresentsastudyontheeffectoftopographicvariabilityoncell-basedempiricalestimationofsoillossandsedimenttransport.AnoriginalDEMof10mresolutionforacasewatershedwasre-sampledtothreerealizationsofhighergridsizesforacomparativeexamination.EquationsbasedontheUSLEareappliedtothewatershedtocalculatesoillossfromeachcellandtotalsedimenttransporttostreams.ThestudyfoundthatthecalculatedtotalsoillossfromthewatersheddecreaseswiththeincreasingDEMresolutionwithalinearcorrelationasspatialvariabilityisreducedbycellaggregation.TheUSLEtopographicfactors(LS)extractedfromappliedDEMsrepresentspatialvariability,anddeterminetheestimationsasshowninthemodelingresults.ThecommonlyusedUSGS30mDEMappearstobeabletoreflectessentialspatialvariabilityandsuitablefortheempiricalestimation.TheappropriatenessofaDEMresolutionisdependentuponspecificlandscapecharacteristics,appliedmodelanditsparameterization.ThisworkattemptstoprovideageneralframeworkfortheresearchintheDEM-basedempiricalmodeling.
简介:文中简要介绍了地理信息系统(GIS)的基本概念和现今农业结构战略性调整的具体内涵,介绍了地理信息系统应用于农业气候区划工作的背景和制作专题农业气候区划的步骤,同时对"3S"集成技术进行了简单的综述.
简介:在地理信息系统(GIS)技术基础上,提出了中国铜矿资源信息系统的总体规划。铜矿资源信息系统分为3个子系统;该系统共包括空间数据库、属性数据库、图像数据库和文档数据库提出如何建立中国铜矿资源信息系统设计构想和实例。
简介:ThepolicyoftheChinesegovernmentconcerningthehorizontalexpansionofthecultivatedlandthroughthereclamationofdesertsoilsresultinatotalincreaseof665.985km2duringtheperiod1987-1999inNorthShaanxi.Thisincreaseislessthanthelossinarablelandbyurbanization.Theacceleratedrateofchangeinagriculturalareascallsformorerapidsurveysofurbanizationandlossofarableland.Remotesensinghasanumberofadvantagesoverground-basedmethodsforsuchsurveys.Themulti-scaleconceptofremotesensingdatahelpusstudytheprobleminfourtowns.Severalmapswereproducedtoanalyzethesituationofurbancoverageindifferenttimes.Theevaluationofthestatus,rateandriskofurbanizationarebasedonanacceptedaverageofurbanincreaseas2%ofpopulationgrowthperyear.
简介:二维地理信息系统远远不能满足人们的要求,取而代之的是建立空间的立体的三维GIS。不规则四面体被认为是最简单的数据表示方法之一,本文就三维Delaunay剖分及其在GIS中的应用作了阐述。