gis题.docx
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gis题.docx
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gis题
《地理信息系统》双语课程辅导题
一、Definethefollowingterms(totalmarksare15,and3marksofeveryone)
1.GeographicInformationSystem
GISismuchmorethanacontainerofmapsindigitalform.
AGISisalsoacomputerizedtoolforsolvinggeographicproblems,
AGISisamechanizedinventoryofgeographicallydistributedfeaturesandfacilities
AGISisatoolforrevealingwhatisotherwiseinvisibleingeographicinformation
AGISisatoolforperformingoperationsongeographicdatathataretootediousorexpensiveorinaccurateifperformedbyhand
2.Tobler'sFirstLawofGeography
Everythingisrelatedtoeverythingelse,butnearthingsaremorerelatedthandistantthings.
3.Spatialautocorrelation
isatermreferringtothedegreeofrelationshipthatexistsbetweentwoormorespatialvariables,suchthatwhenonechanges,theother(s)alsochange.Thischangecaneitherbeinthesamedirection,whichisapositiveautocorrelation,orintheoppositedirection,whichisanegativeautocorrelation.
4.Datamodel
AdatamodelisanessentialingredientofanyoperationalGIS,andtheheartofanyGISisthedatamodel,whichisasetofconstructsforrepresentingobjectsandprocessesinthedigitalenvironmentofthecomputer.
ThereisnosingletypeofGISdatamodelthatisbestforallcircumstances.
5.Metadata
Dataaboutdataandusageaspectsofit.Thisinformationwilloftenincludesomeofthefollowing:
Whatitisabout?
Whereitistobefound?
Whooneneedstoasktogetit?
Howmuchitcosts?
Whocanaccessit?
Inwhatformatitisavailable?
Whatisthequalityofthedataforaspecifiedpurpose?
Whatspatiallocationdoesitcoverandoverwhattimeperiod?
Whenandwherethedatawerecollectedandbywhomandwhatpurposesthedatahavebeenusedfor,bywhomandwhatrelateddatasetsareavailable?
etc.
Metadataareneededfor:
Toenabletheprocessofsearchanddiscoveryoverdistributedarchives;
Toassessthefitnessofadatasetforagivenuse;
Toprovidetheinformationneededtohandlethedataseteffectively;and
Toprovideusefulinformationonthedataset’scontents.
6.Spatialanalysis
Spatialanalysisisanalyticaltechniquesassociatedwiththestudyoflocationsofgeographicphenomenatogetherwiththeirspatialdimensionsandtheirassociatedattributes.
Spatialanalysisisusefulforevaluatingsuitability,forestimatingandpredicting,andforinterpretingandunderstandingthelocationanddistributionofgeographicfeaturesandphenomena.
Spatialanalysiscanrevealthingsthatmightotherwisebeinvisible-itcanmakewhatisimplicitorimplicit.
SpatialanalysisisthecruxofGIS,themeansofaddingvaluetogeographicdata,andofturningdataintousefulinformation.
Effectivespatialanalysisrequiresanintelligentuser,notjustapowerfulcomputer.
Spatialanalysishelpsusinsituationswhenoureyesmightotherwisedeceiveus.
Spatialanalysisisasetofmethodswhoseresultsarenotinvariantunderchangesinthelocationsoftheobjectsbeinganalyzed.
Spatialanalysisisasetofmethodswhoseresultschangewhenthelocationsoftheobjectsbeinganalyzedchange.
7.Classification
Classificationisamethodofgeneralisation.Intheprocessofclassification,anattemptismadetogroupdataintoclassesaccordingtosomecommoncharacteristicstherebyreducingthenumberofdataelements.Classificationtendstobebasedupontheattributesorcharacteristicsofdataratherthantheirgeometry.Indigitalimageprocessing,imagesareusuallyclassifiedaccordingtothespectralpropertiesofthepixelscomposingtheimage.Inspatialanalysis,amapcanbeclassifiedaccordingtoanyattributevalue,forexample,soiltypes,populationdensity,unemploymentetc.Theresultofperformingclassificationisathematicderivedmap.
8.Buffer
Buffer—returnsageometrythatrepresentsallthepointswhosedistancefromthegeometryislessthanorequaltoauser-defineddistance.Givenageometryandabufferdistance,thebufferoperatorreturnsapolygonthatcoversallpointswhosedistancefromthegeometryislessthanorequaltothebufferdistance.
9.DEM
ThetermDEMcanrefertooneofthefollowing:
1.Adigitalrepresentationofacontinuousvariableoveratwo-dimensionalsurfacebyaregulararrayofzvaluesreferencedtoacommondatum.DigitalelevationmodelsaretypicallyusedtorepresentterrainreliefandfrequentlycompriseafoundationallayerinanyarchaeologicalGISdatabase.2.AnelevationdatabaseforelevationdatabymapsheetfromtheNationalMappingDivisionoftheU.S.GeologicalSurvey(USGS).3.TheformatoftheUSGSdigitalelevationdatasets(ESRI1996)
10.Network
Aninterconnectedsetofarcsorlinesrepresentingpossiblepathsforthemovementofresourcesfromonelocationtoanother.
Agroupofcomputersthatarelinked,andareabletoshareperipherals,softwareanddata.TheInternetisprobablythemostwellknownexampleofacomputernetwork.
Atypeofdatabasestructure.Anetworkdatamodelisbasedupontheideaofexplicitlinksbetweenrelatedentities.
二、Cloze(totalmarksare20,and1markforeachblank)
1.ManyrootsofGIScomefromprinciplesofgeography.
2.CanadaGeographicInformationSystemisdevelopedin1963byRogerTomlinsonandcolleaguesforCanadianLandInventory.
3.ArclnfowasthefirstmajorcommercialGISsoftwaresystem.Designedforminicomputersandbasedonthevectorandrelationaldatabasedatamodel,itsetanewstandardfortheindustry.
4.ComponentsofaGISincludes:
Computerhardware,GISsoftware,People,Data,Network,Procedures.
5.Geographicaldatalinkplace,timeandattributes.
6.Geographicalattributesareclassifiedasnominal,ordinal,intervalandratio.
7.GISsoftwaresystemsdealwiththethree-tierarchitecturetoaGIS:
userinterfaces,tools,anddatamanagement.
8.TypesofGISsoftwareincludes:
DesktopGIS,ProfessionalGIS,Server/InternetGIS,Developer/ComponentGIS,Hand-heldGIS,Others(Raster-basedGIS,CAD-basedGIS)
9.Spatialautocorrelationisdeterminedbothbysimilaritiesinposition,andbysimilaritiesinattributes.
10.Rasterdatamodelusesanarrayofcells,orpixels,torepresentreal-worldobjects.Featuresarevectorobjectsoftypepoint,polyline,orpolygon.
11.Toimprovestorageefficiency,manytypesofrastercompressiontechniquehavebeendevelopedsuchasrun-lengthencoding,blockencoding,ChainCodes,andquadtrees.
12.Threekeyhallmarksofobjectorientation:
Polymorphism,Encapsulation,Inheritance.
13.Threekeyaspectsofresolutionare:
spatial,spectral,andtemporal.
14.ExpressionsofDBMSstructurecanbedefinedasFlatfile,Hierarchicaldatastructure,Networkdatastructure,Relationaldatastructure.
15.DBMScanbeclassifiedaccordingtothewaytheystoreandmanipulatedata.3maintypesofDBMS:
relational(RDBMS),object(ODBMS)andobject-relational(ORDBMS).
16.AccordingtothisISO/OGCstandard,ninemethodstotestspatialrelationsbetweengeometries:
Equals,Disjoint,Intersects,Touches,Crosses,Within,Contains,Overlaps,Relate.
17.Anetworkcanberepresenteddigitallybynodesandlinks.
三、TheleftcolumncontainsalistofexplanationorinterpretationofGISterms.Writethetermintheboxtotherightside.(Totalmarksare10,and2markforeveryone)
1.AGeographicalInformationSystemdesignedfortheoptimalprocessingofinformationaboututilitiesandinfrastructuressuchapipes,cablesnetworksandpowerlines.Thesesystemscombinedigitalmappingfunctionalitywithsystemsformanagingspatialandnon-spatialdatabases.
AutomatedMappingandFacilitiesManagement
AM/FM
2.Asetofpointsrepresentingthesamevalueofaselectedattributeandforminganimaginaryline.Itismostcommonlyusedforlinesconnectingpointsonthegroundhavingthesameelevation.
ContourLine
3.Simplificationofmapinformation,sothatinformationremainsclearandunclutteredwhenmapscaleisreduced.Usuallyinvolvesareductionindetail,aresamplingtolargerspacing,orareductioninthenumberofpointsinaline.Traditionallythishasbeendonemanuallybyacartographer,butincreasinglysemi-automatedandevenautomatedmethodshavebeenused,particularlyinconjunctionwithaGIS.
Generalization
4.Theangulardistanceofapointontheerath'ssurfaceeastorwestofanarbitrarilydefinedmeridian,usuallytheGreenwichmeridian(Greenwich,England).TheGreenwichmeridianwasagreedin1884asbeingthecentralmeridianfromwhichallothermeridianswouldbereferencedtoinordertocalculatelongitude.
Longitude
5.Theprocessofsuperimposingtwoormoremaps,throughregistrationtoacommonco-ordinatesystem,suchthattheresultantmapscontainthedatafrombothmapsforselectedfeatures.Althoughthetermoverlaycanbeappliedtopaperbasedmaps,moreoftenitappliestotheuseofdigitaldata,nevertheless,theprincipalisthesame.
Overlay
6.Therelativelocationofgeographicphenomenaindependentoftheirexactposition.Indigitaldata,therelationshipssuchasconnectivity,adjacencyandrelativepositionareusuallyexpressedasrelationshipsbetweennodes,linksandpolygons.
ItisusefulinGISbecausemanyspatialmodellingoperationsdon'trequireco-ordinates,onlytopologicalinformation.
Topology
7.Aformofthetesseralmodelbasedontriangles.Theverticesofthetrianglesformirregularlyspacednodes.
TheTINdatasetincludestopologicalrelationshipsbetweenpointsandtheirneighbouringtriangles.EachsamplepointhasanX,Yco-ordinateandasurface,orZ-Value.Thesepointsareconnectedbyedgestoformasetofnon-overlappingtrianglesusedtorepresentthesurface.Tinsarealsocalledi
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