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1、水利水電技術(shù)第48卷2017年第3期顧及高程歸化的斜軸墨卡托圓柱投影的應(yīng)用研究何嬋軍,邸國(guó)輝(湖北省水利水電規(guī)劃勘測(cè)設(shè)計(jì)院,湖北武漢430064)摘要:針對(duì)某些大型調(diào)水工程?hào)|西跨距較大的特點(diǎn),提出了特殊的減小長(zhǎng)度變形方法,即將原參考橢球膨脹至高程投影面,再將橢球面大地坐標(biāo)投影至圓球面,然后以工程線(xiàn)路的中軸線(xiàn)為偽中央子午線(xiàn)進(jìn)行斜軸墨卡托圓柱投影。結(jié)果表明:斜軸墨卡托圓柱投影可建立統(tǒng)一的、滿(mǎn)足投影變形要求的工程獨(dú)立坐標(biāo)系統(tǒng).可同時(shí)減小高程歸化引起的長(zhǎng)度變形和高斯投影長(zhǎng)度變形,避免了由于多個(gè)分帶導(dǎo)致的誤差和頻繁的坐標(biāo)轉(zhuǎn)換;對(duì)于大型調(diào)水工程投影變形應(yīng)要求不大于10mm/km,則工程線(xiàn)路
2、至線(xiàn)路的中軸線(xiàn)的距離應(yīng)不大于28km,即投影帶的寬度應(yīng)不大于56km。通過(guò)與變形橢球高斯投影方法對(duì)比可知,斜軸墨卡托圓柱投影方法綜合投影變形與前者相當(dāng),但在圓球面上進(jìn)行計(jì)算和分析相對(duì)簡(jiǎn)單方便,容易推廣使用。關(guān)鍵詞:大型調(diào)水工程;斜軸墨卡托圓柱投影;投影變形;橢球膨脹;球面投影doi:10.13928/j.enki.wrahe.2017.03.007中圖分類(lèi)號(hào):TV221.1文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1000—0860(2017)03—0034-06ApplicationandResearchofObliqueMercatorCylindricalProjection弼thElev
3、ationDomesticationHEChanjun,DIGuohui(HubeiProvincialWaterResourcesandHydropowerPlanningSurveyandDesignInstitute,Wuhan430064,Hubei,China)Abstract:Aimedatthefeaturesofsomelarge-scalewaterdiversionprojectsthattheeasttowestcrossing-distanceislarger,aspecialmethodforreducingthelengthdeformationis
4、proposed.First,expandingtheoriginalreferenceellipsoidtotheheightpro。jectionplane;second,projectingtheellipsoidalearthcoordinateontothesphericalsurface;finally,carryingouttheobliqueMer-catorcylindricalproj‘ecfionbytakingthepseudocentralmeridianasthecentralaxis.TheresultshowsthattheobhqueMerca
5、torcylindricalprojectionnotonlyestablishesanintegratedprojectcoordinatesystem,butalsoreducesboththelengthdeformationcausedbytheelevationdomesticationandthelengthdeformationofGaussprojectionatthesametime,thusavoidingtheerrorcausedbyseveralsub.zonesandfrequentcoordinateconversion;withwhichthep
6、rojectiondeformationmustnotsurpass10mm/kmandthedistancefromtheprojectlinetothecentralaxisnotsurpassed28kmforthelarge-scalewaterdiversionpmject,i.e.thewidthoftheprojectionmustnotsurpassed56km.ThroughthecomparisonwimthemethodofthealterationofGaussprojectionbasedonobliquedeformedellipsoid,theco
7、mprehensiveproj‘ectiondistortionfromthemethodofobliqueMercatorcylindricalpro—jectionwithelevationdomesticationisequivalenttothatoftheformer,butissimpleandeasytomakecalculationandanalysisonsphericalsurface,thusispronetobepopularizedforapplication.Ke