简介:Adoptingaprincipleof“check-acceptforthefirstrank,inspectionforthesecondrank”,thispaperbrieflydiscussestherationaleofthesamplinginspectionandthesamplinginspectionschemestodigitalproductsinGIS.TheOCcurveisdrawntoexplainthedeficiencyofthepercentsamplinginspection.Meanwhile,themethodofOneTimeLimitingQualityofcountselectionispresentedastheinspectionschemeforproductiondepartmentswhilethemethodofOneTimeAfter-inspectionMeanPercentDefectiveUpperLimitofcountselectionisforacceptancedepartments.
简介:摘要地理信息系统是空间和空间各属性的集合。涵盖地矿、天气、交通等多种领域,地理信息系统对于铁路的辅助决策有相当大的意义。对铁路的建设、各种资源的运输,铁路各项运营资源调配的优化设计具有引领性的作用,对未来运输行业的发展具有深远的影响。
简介:Ithasbeendebatedthatwhichofrasterandvectoristhemosteffective,fromtheviewpointsofstorageefficiency,processingefficiency,andabilitytocapturetheessenceofgeographicspaceforanapplication.Theremaybenoclearanswertothisdebate.Itseemsappropriatetonotethatthemaindifferencebetweenthemrelatestothedegreetowhichthespatialentitiesofinterestareexplicitinthedata. Ingeneral,rasterremotesensingimageallowstheinvestigatortomeasureandmonitorsurfaceelectromagneticwavevariationinwhichmostobjectsandthespatialinterrelationshipsbetweenthemareimplicit.Inpractice,therearemanypoorlyunderstoodtradeoffsincouplingremotesensingdatatoexistingthematicmaps.Mapsusepointsandlinestorepresentselectedfeaturesoftheenvironmentinageneralizedfashion,buttheobjectssuchasindividualpolygons,linesandpointswithinanimagearetypicallyunknown. TheintegrationofremotesensinginformationintoaGISoccursnaturallyinarasterGISbecausebothdatastructuresareapproximatelythesame.Integrationintoavectorsystemrequiressomewhatmoreeffort,butithasbeenrecentlyachievedbyseveralGISandremotesensingvendors.Whenoneisstoringalargeamountofimagedatarelatedtosomeapplicationsintoaspatialdatabasesystem,itisnotpossibletoprocessthedataandtoobtainpolygonalrepresentationsofallobjectsthatwillbeofinteresttousersinadvance.Ontheotherhand,itmightbeofgreatvalueinsuchasystemtohaveavectorrepresentationofcertainimportantobjects.Forthisapplication,oneneedstodesignasystemwithbothrasterandvectorcapabilities,aswellastoolstointerrelatethem.Especially,asinFig.1,weneedtoprocessbothrasterandvectorsimultaneously. Asdescribedabove,whileaspatialinformationsystemmayhaveseveraldatastructures,thesystemcouldbeextendedinseveralwayswhichcorrespondtothefollowingdifferentproperties(seeFig.2): 1)Thestuructureinforma