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: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:ThepolicyoftheChinesegovernmentconcerningthehorizontalexpansionofthecultivatedlandthroughthereclamationofdesertsoilsresultinatotalincreaseof665.985km2duringtheperiod1987-1999inNorthShaanxi.Thisincreaseislessthanthelossinarablelandbyurbanization.Theacceleratedrateofchangeinagriculturalareascallsformorerapidsurveysofurbanizationandlossofarableland.Remotesensinghasanumberofadvantagesoverground-basedmethodsforsuchsurveys.Themulti-scaleconceptofremotesensingdatahelpusstudytheprobleminfourtowns.Severalmapswereproducedtoanalyzethesituationofurbancoverageindifferenttimes.Theevaluationofthestatus,rateandriskofurbanizationarebasedonanacceptedaverageofurbanincreaseas2%ofpopulationgrowthperyear.