《地理信息系统GIS》PPT课件

GeographicInformationSystem-地理信息系统-,主讲：史良胜副教授武汉大学水利水电学院,课程内容及学时分配,教材及参考资料,1.GeospatialAnalysis:AcomprehensiveGuidetoPrinciples,TechniquesandSoftwareTools,ThirdEdition(Smithetal.,2009).Theonline-versioncanbeaccessedvia,考核办法,课堂表现：20%作业情况：20%期末考试：60%,GeographicInformationSystemGIS,Introduction,WhatisGISInthebeginning.thereweremapsRasterandvectorGIS=software+data.ThesignificanceofscaleBasicfunctionsofGIS,GeographicInformationSystemGIS,WhatisGIS？,intuitivedescription,Amapwithadatabasebehindit.Avirtualrepresentationoftherealworldanditsinfrastructure.,GeographicInformationSystemGIS,System:Agroupofelementsorganizedinsuchawaythateveryelementistosomedegreeinterdependent(directlyorindirectly)witheveryotherelement.ex)Ecosystem,TransportationSystem,ManufacturingSystem,GeographicInformationSystemGIS,WhatisGIS?,Information:-.Datavs.Information-.Data:acquisitionthroughdirectobservationorsurvey-.Information:thedatabecomeinformationwheninterpretedinsomemeaningfulway,GeographicInformationSystemGIS,WhatisGIS?,InformationSystem:DatabaseSystem,DataProcessingSystem-.Designedtoinputdata,storeit,manageit,processit,andoutputitintheformofmeaningfulinformationGeographicInformationSystem:Acomputer-basedinformationsystemthatenablescapture,storage,retrieval,sharing,manipulation,analysis,modeling,andpresentationofgeographicallyreferenceddata.,GeographicInformationSystemGIS,WhatisGIS?,GeographicInformationSystemGIS,“Acomputersystemforcollecting,checking,integratingandanalyzinginformationrelatedtothesurfaceoftheearth.”(Rhind,1988),Inotherwords,GISisbothadatabasesystemwithspecificcapabilitiesforspatiallyreferenceddataaswellasasetofoperationsforworkingwiththedata.Itmayalsobeconsideredasahigherordermap.,GeographicInformationSystemGIS,WhatisGIS?,Setoftoolsforcollecting,storing,retrievingatwill,transforminganddisplayingspatialdatafromtherealworldforaparticularsetofpurposes(Burrough,1986),acomputerbasedsystemthatprovidesfoursetsofcapabilitiestohandlegeo-referenceddata:datainputdatamanagement(datastorageandretrieval)manipulationandanalysisdataoutput.(Arnoff,1989),GeographicInformationSystemGIS,WhatisGIS?,GeographicInformationSystemGIS,WhatisGIS?,acomputerbasedsystem,spatiallyreferenceddata,input,manage,analysis,output,share,AdvantagesofGIS,GISisgoodathandlingspatialdatavisualisationofspatialdataintegratingspatialdataframeworkfor:analysisandmodellingdecisionsupport,GeographicInformationSystemGIS,(dis)AdvantagesofGIS,GISisnotsogoodathandlingtemporaldatavisualisationoftemporaldataintegratingspatialandtemporaldataframeworkfor:analysisandmodellingoftimedependentdatavolumetricanalysisuncertainty,GeographicInformationSystemGIS,GeographicInformationSystemGIS,Introduction,WhatisGIS?Inthebeginning.thereweremapsRasterandvectorGIS=software+data.ThesignificanceofscaleBasicfunctionsofGIS,GeographicInformationSystemGIS,Withoutmap?,ThestoryofGISbeginsintheworldofmaps.,Thenaturalenvironmentisextremelycomplexhighlyvariable(spaceandtime)complicatedfurtherbyhumanaction,GeographicInformationSystemGIS,2.1Maptypes,GeographicInformationSystemGIS,ATopographicmapshowsthephysicalsurfacefeatures,forexample,roads,rivers,buildings.,AContourmapshowslineswhichconnectpointlocationsatwhichacertainpropertyhasthesamevalue,forexample,heightabovesealevel,isobarsshowingairpressure.,AChoroplethmapshowsareascharacterisedbysomegeneralcommonfeature,forexample,politicalmaps,agriculturalcroptypes.,2.2Mapfeatures,allmapfeaturescanbedividedintooneoffourdifferentcategories:,GeographicInformationSystemGIS,?,Point(forexample,acrosssymboltorepresentachurch).Line(forexample,ayellowlinetorepresentaroad).Polygonshapeorarea(forexample,ablueareatorepresentalake).Text(forexample,thenameofabuilding).,2.2Mapfeatures,GeographicInformationSystemGIS,Howismapinformationtranslatedintodigitalformandreadbyacomputer?TheGISmustbeabletostoreinformationabout:Thegeometry:theshapeandlocationoftheobjects.Theattributes:thedescriptiveinformationknownabouttheobjects,normallydisplayedonamapthroughsymbologyandannotation.,2.3Mapinformation,GeographicInformationSystemGIS,SpatialComponentLocationInformationWhereisit?AllofthedatainaGISaregeoreferenced.AttributeComponentDescriptiveInformation(characteristics)Whatisit?,GeographicInformationSystemGIS,GeographicData:,Spatial+Attribute.,GeographicInformationSystemGIS,GeographicData:,GeographicInformationSystemGIS,Introduction,WhatisGIS?Inthebeginning.thereweremapsRasterandvectorGIS=software+data.ThesignificanceofscaleBasicfunctionsofGIS,GeographicInformationSystemGIS,3.1Mapsinbits,Computersstoreinformationinsequencesofbinarydigits(bits),whichformacodeforeverypossiblenumberorletter.,GeographicInformationSystemGIS,Thisfitswiththewaymapsreferencegeographicallocationsontheearthssurface,throughasystemofcoordinates.,Alllocationsandshapescanbedefinedintermsofxandycoordinatesfromagivengridsystem:itisthesenumericalvalueswhichareusedtotranslatemapinformationintodigitalform.,GeographicInformationSystemGIS,3.2Vectordata,Therearetwofundamentalmethodsofstoringmapinformationindigitalform,rasterandvector.,Invectordatathefeaturesarerecordedonebyone,withshapebeingdefinedbythenumericalvaluesofthepairsofxycoordinates.Apointisdefinedbyasinglepairofcoordinatevalues.Alineisdefinedbyasequenceofcoordinatepairsdefiningthepointsthroughwhichthelineisdrawn.Anareaisdefinedinasimilarway,onlywiththefirstandlastpointsjoinedtomakeacompleteenclosure.,GeographicInformationSystemGIS,Invectordatathepositionandshapeofthebuildingiscapturedasaseriesoffourpairsofnumericalcoordinates.,GeographicInformationSystemGIS,3.3Rasterdata,Inrasterdatatheentireareaofthemapissubdividedintoagridoftinycells.Avalueisstoredineachofthesecellstorepresentthenatureofwhateverispresentatthecorrespondinglocationontheground.Rasterdatacanbethoughtofasamatrixofvalues.,GeographicInformationSystemGIS,Thevaluesrecordedinthecellsareeitherwhite,blueorred.Toreproducetheimagethecomputerreadseachofthesecellvaluesonebyoneandappliesthemtothepixelsonthescreen.,GeographicalInformationSystemGIS,3.4VectorvRaster,Vector:RelativelylowdatavolumeFasterdisplayCanalsostoreattributesLesspleasingtotheeye,Raster:RelativelyhighdatavolumeSlowerdisplayHasnoattributeinformationMorepleasingtotheeye,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,Inthisexampletherasterdatalooksnicerbut,asyouzoomin,thepixelstructurebecomesobvious.Eventuallytheimagelookslikeapieceofmodernartratherthanadetailofamap!Thedefinitionofthefeaturesisdependentuponthesizeoftheindividualgridcellstheresolution.Thevectordataismorelikeagraphwithalinedrawnbetweenpoints,thewidthstayingthesamehowevercloseyouzoom.,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,Introduction,WhatisGIS?Inthebeginning.thereweremapsRasterandvectorGIS=software+data.ThesignificanceofscaleBasicfunctionsofGIS,GeographicalInformationSystemGIS,AnysuccessfulexampleofGISisbasedontwofundamentalcomponents:themapdata;andthecomputersoftwaretoperformcalculationsandanalysis.,GeographicalInformationSystemGIS,TherearemanydifferentorganisationsproducingdataforuseinGIS;,ThereisalsoalargeindustryinGISsoftwarewithhundredsofcompaniesproducingthousandsofproducts.,Software:GISSoftwareArcGIS(ArcInfo,ArcView),MapInfo,etc.DatabaseMSAccess,Oracle,Sybase,dBASESpatialDataAnalysisS-PLUS,SPSSInternetMappingSystem-ArcIMSSystemAnalysisToolCASE,Visio,ModelBuilder,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,People:ITAdministratorsGISAnalystsGISTechniciansApplicationExpertsSpatialDataAnalystEndUsers,GeographicalInformationSystemGIS,Hardware:Computer(PCorUNIX)Digitizer/ScannerPlotter/PrinterNetworkSystem/GPSUnitsCD-ROMorDataStorageDevices,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,Introduction,WhatisGIS?Inthebeginning.thereweremapsRasterandvectorGIS=software+data.ThesignificanceofscaleBasicfunctionsofGIS,GeographicalInformationSystemGIS,5.1Scalebasics,Adescriptionofscalecanloseitsmeaningthescaleoftheimageonscreencandependonthemonitorsize.Theimageabovemayappear13mmlongonsomescreensbutnotothers.,GeographicalInformationSystemGIS,5.2Scaleofcapture,AllGISpackagesenableyoutozoominandoutonthemapdataasmuchasyoulike.However,alltopographicdatahasascaleofcapture,thatis,thesourcedatawascapturedataparticularscale,whetherthiswasapapermaporanaerialphoto.,GeographicalInformationSystemGIS,Itisimportanttounderstandthesourcescaleofyourdatafortwofundamentalreasons:datafromaparticularscaleshouldonlybeviewedwithinacertainrangeofmagnificationforittomakesensevisually;andcombiningtwoormoredatasetstogetherisonlyappropriateiftheyhaveanequivalentscaleofcapture.,5.2Scaleofcapture,GeographicalInformationSystemGIS,5.3Generalisation,Themappingthatmostofusrecognisehasbeendeliberatelysimplified.,GeographicalInformationSystemGIS,5.3Generalisation,Themappingthatmostofusrecognisehasbeendeliberatelysimplified.,GeographicalInformationSystemGIS,5.3Generalisation,Themappingthatmostofusrecognisehasbeendeliberatelysimplified.,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,5.3Generalisation,Themappingthatmostofusrecognisehasbeendeliberatelysimplified.,GeographicalInformationSystemGIS,GeographicalInformationSystemGIS,5.3Generalisation,Themappingthatmostofusrecognisehasbeendeliberatelysimplified.,large-scaledatawhenviewedatasmallscale(zoomedout),appearsclutteredwhereassmall-scaledatawhenviewedatalargescale(zoomedin),appearsverysparse.,Acartographercreatesthesesimple,readablemapsbyselectinginformationfromalarger-scalesource.Notallthedetailfromthesourcemapcanbeshown.,GeographicalInformationSystemGIS,5.3Generalisation,Sometimesitmaybenecessarytoalterafeaturestruesurveypositionslightlytomakespaceforthemapsymbols.Furthermore,thethickredlinesofanAroadareshownmuchwideronthemapthantheactualroadisontheground.Thisscienceofsmall-scalemapproductionisknownasgeneralisation.,GeographicalInformationSystemGIS,5.3Generalisation,GeographicalInformationSystemGIS,5.4Becarefulwithscale,ManyGISdataproductsarecreatedfromgeneralisedmapsources,Theeffectsofgeneralisationwillshowupifthisdataisviewedagainstothermorelarge-scalemapping.,GeographicalInformationSystemGIS,5.4Becarefulwithscale,Thegeneraliseddataisnotwrong,itisjustbeingmagnifiedmorethanwaseverintended.,Whenyouzoomin,thedeviationofthesimplifiedfeaturesfromtheirsurveypositionisapparentwhenthelarge-scaledatabecomesvisible.,GeographicalInformationSystemGIS,Introduction,WhatisGIS?Inthebeginning.thereweremapsIntroducingrasterandvectorGIS=software+data.aformulaforsuccessThesignificanceofscaleBasicfunctionsofGIS,GeographicalInformationSystemGIS,BasicfunctionsofGIS?,GeographicalInformationSystemGIS,SomeexamplesofGISinAction:,LandUsePlanning,GeographicalInformationSystemGIS,SomeexamplesofGISinAction:,Monitoringofdeforestation,Source:UCBerkeleyGISCenter,GeographicalInformationSystemGIS,SomeexamplesofGISinAction:,Findtheleastcostbikeroute(intermsoftrafficandslope)fromandtotwouserdefinedpoints,GeographicalInformationSystemGIS,SomeexamplesofGISinAction:,3DVisualizationandTerrainAnalysisfortransportationplanning,Watersheddelineationusingdigitalelevationmodels,GeographicalInformationSystemGIS,SomeexamplesofGISinAction:,Source:Geonmonics,Inc.,GeographicalInformationSystemGIS,SomeexamplesofGISinAction:,Siteanddemographicanalysisforretail/officelocation,DataInput(DataModel,DataMeasurement)Datastorage,retrievalanddatabasemanagementDataanalysis(manipulation,transformationexplorationandconfirmation)Output(displayandproductgeneration),GeographicalInformationSystemGIS,BasicFunctionsofGIS,Datacapture/input:Inputdatabydigitizing,scanning,ordirectcoordinateentryEditdataintheGIStocorrecterrorsoraddfeaturesLabelthespatialfeaturessotheycanbeidentified(namesorcodes),GeographicalInformationSystemGIS,BasicFunctionsofGIS,Management:LinkattributedatatospatialobjectsLinktoexternaldatabasesMakechangesinexistingdatabasesUpdatedatabasefeaturesImportandexportfrom/tootherGISorDBMSCombinemapsheetstocreatelargedatabasesmatchtheedgesofneighboringmapsheets,GeographicalInformationSystemGIS,BasicFunctionsofGIS,Manipulation:MakemapsfromdifferentsourcescompatiblesothattheycanbedrawnontopofeachotherTransformationofcoordinatesProjectionchange,GeographicalInformationSystemGIS,BasicFunctionsofGIS,Analysis:QuerySelectfeaturesbytheirattributes:“findalldistrictswithliteracyrates60%”Selectfeaturesbygeographicrelationships:“findallfamilyplanningclinicswithinthisdistrict”Combinedattributes/geographicqueries:“findallvillageswithin10kmofahealthfacilitythathavehighchildmortality”,GeographicalInformationSystemGIS,BasicFunctionsofGIS,Analysis(cont.):Buffer:findallsettlementsthataremorethan10kmfromahealthclinicPoint-in-polygonoperations:identifyforallvillagesintowhichvegetationzonetheyfallPol