毕业设计论文外文文献翻译.docx
《毕业设计论文外文文献翻译.docx》由会员分享,可在线阅读,更多相关《毕业设计论文外文文献翻译.docx(20页珍藏版)》请在冰豆网上搜索。
毕业设计论文外文文献翻译
南京航空航天大学金城学院
毕业设计(论文)外文文献翻译
系部
软件工程
专业
计算机科学与技术
学生姓名
蒋晨
学号
2012022113
指导教师
李海林
职称
讲师
2016年4月
EnvironmentalModelling&Software
1.Introduction
OverthelastdecadestheamountofgeospatialdatahasgrownrapidlyasaresultofthenumberofsatellitesandtheuseofGlobalPositioningSystems(GPS).Toassistintheanalysisandvisualizationofallthisdata,severalgeographicinformationsystems(GISs)andWebGISsiteshavebeendeveloped(SteinigerandHunter,2012).SomeoftheWebGISsitessharecommonfunctionalities,suchasaccesstorawdataortheabilitytooverlapdifferentlayers(Kulawiaketal.,2010;Karnataketal.,2012;NairandKatiyar,2011).WebGISsitesthatdisplayenvironmentaldata,likethePacificIslandsOceanObservingSystem(Voyager)ortheWebGISsitesdevelopedbytheEuropeanEnvironmentAgency,haveanevenlargersetofcommonfeatures,suchastheabilitytoidentifylayerdataatanycoordinate,andthecapabilitytoplotdatainrealtime.However,tothebestofourknowledge,anyopensourceprogramthatautomaticallygeneratesWebGISsiteswithaminimumsetoffeaturesthatallowefficientpublicationof4Dgeospatialdata.
AcommonprocedureforpublishinggeoreferenceddataonaWebGISsiteincludesthefollowingsteps.First,generatethedatatobepublished.Then,uploadthedataintoamapserversuchasMapServer(Kropla,2005),GeoServer(Deoliveira,2008),ArcMapServer,ncWMS(Bloweretal.,2013),etc.Finally,withagroupofprogrammersandwebdesigners,buildthewebinterface(theWebGISsite)todisplaythedatafortheuser.Thisinterfaceprovidesseveralwaystovisualizeandservedata,and,evenwhenmostWebGISsitesdonothavedirectaccesstothedata,theynormallyobtainthedatathroughmapsevers.Thesoftwaredescribedinthispapergreatlysimplifiesthefinalstep,buildingWebGISsites,thusreducingthetimeandcostsforpublishinggeospatialdataontheweb.
FreeandOpenSourceSoftware(FOSS)thathelpsbuildingWebGISsitesalreadyexists.Fig.1,adaptedfromSteinigerandHunter(2013),showstheFOSSGISsoftwarethatisavailabletoaidpublishinggeographicdataonthewebatanyofthepreviouslydiscussedsteps.ThesoftwareintheDesktopGIScategoryareprogramsthatrunonpersonalcomputersandareabletodisplay,query,update,andanalyzegeographicdata.QuantumGIS(ShekharandXiong,2007)andGRASS(Neteleretal.,2012)aretwoofthemostmatureFOSSdesktopGISprograms.Thesetwoprogramscanaccomplishamultitudeoftasksandhavebeenusedtoprepareandanalyzeenvironmentaldataforseveralprojects(Gkatzofliasetal.,2013;Grinandetal.,2013).
TheWebMapServerscategoryaccommodatessoftwarethatprovidesseveraloptionstoaccessandvisualizegeoreferenceddatathroughstandardsoftheOpenGeospatialConsortium(WebMappingServices(WMS)(delaBeaujardiere,2006),WebFeatureServices(WFS)(Vretanos,2005),andWebCoverageServices(WCS)(Baumann,2010)).Thetwobest-knownwebmapserversareMapServerandGeoServer,bothofthemoffervectorandrastersupportandhavecomparablefunctionalitytosimilarproprietarysoftware(SteinigerandHunter,2013).
Fig.1.Simplifiedschemeofthefreeandopensourcegeographicinformationsoftwarefortheweb.Adaptedfrom.SteinigerandHunter(2013).
Anotherwebmapserver,thatisworthmentioningfortheenvironmentalmodelingcommunity,isthencWMSwhichhastheparticularfeatureofbeingabletoserve4DdatastoredasNetCDFfiles,awidelyusedfileformatforstoringenvironmentalmodeldatasets(RewandDavis,1990).TheDEFENSE(Tirantietal.,2014),andtheinteractivevisualizationsystembyKulawiaketal.(2010)aresomeexamplesofenvironmentaldecisionsupportsystemsthatuseFOSSwebmapservers.
TheWebGISlibrariesandtheWebMapDevelopmentFrameworksaretwocategoriesthatencompassGISsoftwareusedtobuildthefinalinterfacetodisplaygeographicdataasdynamicmapsontheweb.ThewebGISlibrariesareapplicationprogramminginterfaces(API's)forthevisualizationandmanipulationofspatialdatathatimplementtheWMS,WFS,etc.OpenLayers(Hazzard,2011)isoneofthemostextensivelibrariesinthiscategory,itisimplementedinJavaScript.Finally,thesoftwareintheWebMapDevelopmentFrameworkscategory,contributewithtoolsforcreatingadvancedwebapplications.TheseframeworksusethewebGISlibrariesandcontaintoolsforthemanagementoflayers,menus,andthemesoftheWebGISsites.SomewellknownprogramsinthiscategoryareMapbender3(http:
//mapbender3.org/),GeoMajas(http:
//www.geomajas.org/),MapFish(http:
//www.mapfish.org/)andGeoMOOSE(http:
//www.geomoose.org/).OWGISbelongstothislastcategoryasitgivesaneasywaytodevelopWebGISsitesthroughtheconfigurationofXMLfiles.ThemainfeaturethatdifferentiatesOWGISfromtherestofthedevelopmentframeworksisthesetoftoolsthatOWGISprovidestovisualize4Ddatathroughtheweb.
OWGIS(http:
//owgis.org/),originallyOpenWebGIS,isanopensourcesoftwarethatcreatesself-containedWebGISsiteswithcommonfeaturesusedbythescientificcommunity.OWGISisaJavawebapplicationthatgenerateswebsitesbyautomaticallywritingHTMLandJavaScriptcode.ThewebsitesbuiltwithOWGISareconfiguredbyXMLfilesandcanaccommodatemapswithlayersservedthroughanymapserver,suchasGeoServer,thatcomplieswiththeWMSstandard.OWGISisalsocapableofconstructingWebGISsitesthatdisplay3DdataservedbytheTHREDDSservers(Domenicoetal.,2006)orthencWMSservers,usingtheWMSextensionproposedbyBloweretal.(2013).
ThecurrentfeaturesthatOWGISprovidesonthegeneratedWebGISsitesare:
multiplelanguages,animations,mobileinterface,ContextualQueryLanguage(CQL)filtering(http:
//en.wikipedia.org/wiki/Contextual_Query_Language),identifyfeatures,theabilitytodownloaddataasKML,GeoTIFForshapefiles,andthecapacitytoplotverticalprofilesandverticaltransectsatdifferentlocations.ThoughsomeofthesefeaturesarealreadyavailableinmanyWebGISsites,regardlessofwhetherornottheydisplayscientificdataorothertypesofgeographicdata,OWGISallowsbuildingandmaintainingnewsiteswithallthesefeaturesbysimplyeditingXMLfiles.
OWGISisbeingdevelopedattheCenterforOcean-AtmosphericPredictionStudies(COAPS),FloridaStateUniversity(FSU),incollaborationwiththeUniversidadNacionalAutonomadeMexico(UNAM).OWGISiscurrentlyusedastheinteractivevisualizationmapoftheDigitalClimaticAtlasofMexico(Zavala-Hidalgoetal.,2010),whichhasbeenavailablesince2009andprovidesaccesstomorethan2000layersofoceanicclimate,climatechangescenarios,bioclimaticparameters,andsocioeconomicindicators,amongothervariables.OWGISisalsousedbytheDeep-CConsortium(http:
//deep-c.org/)todisplayoceanographicdatafromtheGulfofMexico.
Thepaperisorganizedasfollows.Section2describesthearchitectureofOWGISandthedesignprinciplesthatitfollowswhencreatingwebsites.Section3explainshowtoconfigureOWGISfornewapplications.Section4illustratesthecurrentfeaturesprovidedbyOWGIS.Section5describesaspecificcasestudywhereOWGISissuccessfullyusedtodisplayoceandatafromtheGulfofMexico.Section6endswithadiscussiononthepresentedsoftwareandoutlinessomefuturefunctionalityofOWGIS.
2.Architecture
LikeotherJavawebapplications,OWGIScanbecontainedinawebarchive(WAR)filethatcanbedeployedinanyservletcontainer,suchasApacheTomcat.Similartoacommonwebapplication,OWGIScreateswebcontent,JavaScript,andHTML;howeverwithOWGIS,thefinalwebsitesareself-containedWebGISsites.TheJavaScriptcodegeneratedbyOWGISusesOpenLayers(http:
//openlayers.org/),anopensourcelibraryforcreatingdynamicmaps.OWGISalsocreatescustomJavaScriptcodeforrequestingdatafromserversthatcomplywiththeWMSandWFSstandards.
OWGIS-createdwebsitesdisplaylayersthatareservedthroughmapservers.Theinformationabouteachlayer,suchasthenameofthelayer,isconfiguredusingXMLfiles.ThesefilesareusedtomodifythelookandcontentoftheOWGISsitesandaredescribedinSection3.OWGISmonitorsanychangestothesefiles,madebytheadministrators,andisabletoupdatewebsiteswithoutreloadingthewebapplicationontheserver.Thisfeatureisveryusefulwhenthedatabeingdisplayedonthemapismodifiedoften.Fig.2showsasimplediagramoftheprocessusedbyOWGIStogeneratewebcontentfortheuser.
WhenausermakesanewHTMLrequest,OWGISverifiesthathavebeennomodificationstotheXMLconfigurationfiles.Iftherehavebeenanychanges,OWGISparsesalltheinformationintheXMLfilesandrebuildsinternaldatastructuresforthesites.Oncetheinformationisstoredinternally,OWGISusesittobuildthedesiredinterface,takingintoaccountthespecificuserrequest.
TheOWGISsourcecodeisdividedinfourgeneralmodules:
model,business,servlets,andtools.ThemodelmodulestoresallthelayersobtainedfromtheXMLfilesaswellasthemenusinasetofdatastructures.Theservletsmodulecontainsalltheservlets,whichareinchargeofreceivingnewrequestsfromtheuserandredirectingeachrequesttothepropermethodinthebusinessmodule.TheservletsmodulealsosendscustomizedJavaScriptcodetotheuser.Thebusinessmoduleisinchargeofreadingthecurrentuser'sconfigurationandthedataofthemodelmoduletobuildtheproperJavaScriptcodefortheuser.Thetoolsmodulecontainsanumberofstaticfunctionsusedtocreatewebcontent.
2.1.Designprinciples
Fig.2.SimplifiedschemeofOWG