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1、南京師范大學(xué)博士學(xué)位論文無(wú)網(wǎng)格DEM構(gòu)建關(guān)鍵技術(shù)研究姓名：朱瑩申請(qǐng)學(xué)位級(jí)別：博士專業(yè)：地圖學(xué)與地理信息系統(tǒng)指導(dǎo)教師：劉學(xué)軍20090517摘要5．研究了基于無(wú)網(wǎng)格法進(jìn)行地形因子與流域網(wǎng)絡(luò)的提取。根據(jù)無(wú)網(wǎng)格法中導(dǎo)數(shù)求解方法和現(xiàn)有坡度坡向求解公式，給出了各點(diǎn)坡度坡向的計(jì)算方法。研究微分幾何中主曲率與主方向的求解方法，以及地形中匯水線的數(shù)學(xué)性質(zhì)，給出了提取匯水線上特征點(diǎn)的方法。研究將提取的特征點(diǎn)連接成為匯水線網(wǎng)絡(luò)的方法。本研究通過(guò)無(wú)網(wǎng)格法構(gòu)建一種靈活可變的散點(diǎn)結(jié)構(gòu)的DEM，采用曲面模型的地形表達(dá)方法。解決了網(wǎng)格所帶來(lái)的限制，為無(wú)網(wǎng)格法應(yīng)用于地學(xué)模型提供了基礎(chǔ)。關(guān)
2、鍵詞：數(shù)字高程模型無(wú)網(wǎng)格法重構(gòu)核近似支撐域斷線形函數(shù)ⅡAbstraetAbstractAsoneofthemostimportantfundamentalgeographicdatainGIS，DEM(DigitalElevationModel)isthedigitalexpressionoflocalrelief,whichusesscatteredpointstosimulatecontinuoustopographicalsurface．DTA(DigitalTerrainAnalysis)istopographicinformationproces
3、singtechnologywhichisusedtocalculatetopographicattributesandextractfeaturesbasedonDEM．DEMandtheresultsfromDTAprovidetopographicparametersforvariousgeographymodels．TerrainfeaturesCallbedepicted，analyzedandextractedthroughDEM，andthesearethefundamentalmaterialsandbasicinformationfore
4、arthscience．AlthoughDEMplaysanimportantrole，、jl，itllmorefocusonGISandgee-scienceanalysis，GridGISdatausuallyrepresentsinconsistent塒mgeographymodels，whichresultsingridproblemsandalsoscaleeffect．ThemostrepresentativeproblemisMAUP(ModifiableArealUnitProblem)inecology．Meshfreemethoddoe
5、sn’tneedpredefinedgridinformationtodiseretizedomainwhensettingupthemodelofentireproblemdomain．Meshfreeapproximationisconstructedbynodes，SOithasadvantagesinsolvinggreatdeformationanddynamicdiscontinuityproblems．Thismethodisflexible，andnodesCanbeaddedordeletedfreelyduringcalculation
6、,soit’Seasytoachieveadaptiveanalysisandalsohigllcalculationaccuracy．MeshfreemethodprovidesanewwayforDTA．Topographyexpressionandterrainanalysisbasedonmeshfreemethodhavebeenthefoundationforsolvinggridproblems，providingfurtherpossibilitytoapplymeshfreemethodtogee·sciencemodels．Thisst
7、udyintroducesmeshfreemethodtoconstructDEMandappliesittoDTA，themainresearchesandinnovationsareasfollows：1．Meshfreemethodanditsapproximationsaresystematicallyreviewedandanalyzed，thecharacteristicsofmeshfreeapproximationconstructingmethodarelearned，andtheirsuitabilityforterrainexpres
8、sionisanalyzed．2．Adaptivemethodof
