測繪工程專業(yè)英語課文翻譯Unit-15Map Projection

Unit15MapProjection(投影地圖)MapprojectionsareattemptstoportraythesurfaceoftheEarthoraportionoftheEarthonaflatsurface.Somedistortionsofconformality,distance,direction,scale,andareaalwaysresultfromthisprocess.Someprojectionsminimizedistortionsinsomeofthesepropertiesattheexpenseofmaximizingerrorsinothers.Someprojectionsareattemptstoonlymoderatelydistortalloftheseproperties.Noprojectioncanbesimultaneouslyconformalandarea-preserving.(地圖投影是在平面上描繪地球或部分地球表面的投影。保形、距離、方向、規(guī)模和地區(qū)總是有些扭曲，結(jié)果F只讀此過程。一些預(yù)測最大限度地減少這些屬性的扭曲，犧牲最大限度地在別人的錯誤。所以我的預(yù)測是試圖模式地歪曲一切這些屬性。沒有投影可以同時保形和保面積。)Conformality:Whenthescaleofamapatanypointonthemapisthesameinanydirection,theprojectionisconformal.Meridians(linesoflongitude)andparallels(linesoflatitude)intersectatrightangles.Shapeispreservedlocallyonconformalmaps.(協(xié)調(diào)：當(dāng)規(guī)模的地圖，在地圖上的任何一點在任何方向上的投影是一樣的，形。經(jīng)線（經(jīng)線）和緯線（緯線）相交于直角。保形映射局部保持形狀。)Distance:Amapisequidistantwhenitportraysdistancesfromthecenteroftheprojectiontoanyotherplaceonthemap.(距離：當(dāng)?shù)貓D描繪從投影中心到地圖上任何其他位置的距離時，地圖是等距的。)Direction:Amappreservesdirectionwhenazimuths(anglesfromapointonalinetoanotherpoint)areportrayedcorrectlyinalldirections.(方向：地圖保留方向時方位角（角度從線路上的一個點到另一點）被描繪在所有方向正確。)Scale:ScaleistherelationshipbetweenadistanceportrayedonamapandthesamedistanceontheEarth.(尺度：尺度是一個距離的MAP和地球上的相同距離之間的關(guān)系。)Area:WhenamapportraysareasovertheentiremapsothatallmappedareashavethesameproportionalrelationshiptotheareasontheEarththattheyrepresent,themapisanequal-areamap.(區(qū)：當(dāng)一個地圖描繪區(qū)域在整個地圖上，所有映射的區(qū)域具有相同的比例關(guān)系的地區(qū)在地球，他們表示，MAP是平等的地區(qū)地圖。)ClassificationofMapProjection(地圖投影分類)Mapprojectionsaregenerallyclassifiedintofourgeneralclassesaccordingtocommonproperties(cylindricalvs.conical,conformalvs.area-preserving,etc.),althoughsuchschemesaregenerallynotmutuallyexclusive.(地圖投影一般分為四個一般類，根據(jù)共同的屬性（圓柱比。圓錐，共形對。區(qū)域保存等），雖然這種方案屬而不是相互排斥。)Cylindricalprojectionsresultfromprojectingasphericalsurfaceontoacylinder.Acylindricalprojectioncanbeimaginedinitssimplestformasacylinderthathasbeenwrappedaroundaglobeattheequator.Ifthegraticuleoflatitudeandlongitudeareprojectedontothecylinderandthecylinderunwrapped,thenagrid-likepatternofstraightlinesoflatitudeandlongitudewouldresult.Themeridiansoflongitudewouldbeequallyspacedandtheparallelsoflatitudewouldremainparallelbutmaynotappearequallyspacedanymore.Inrealitycylindricalmapprojectionsarenotsosimplyconstructed.Thethreeaspectsofthecylindricalprojectionsareasfollows:(柱面投影是將球面投影到圓柱體上的結(jié)果。一個圓柱投影可以想象的最簡單的M作為一個圓柱體已被包裹在一個地球赤道。如果經(jīng)度和緯度的經(jīng)緯網(wǎng)投影到圓柱和圓柱非W敲擊，然后網(wǎng)格狀的經(jīng)度和緯度的直線模式研究ULT。經(jīng)度的經(jīng)度是相等的，緯度的平行度是平行的，但不會出現(xiàn)同樣的距離。實際上柱面投影是不是那么簡單的構(gòu)造。圓柱投影的三個方面如下：)●Tangentorsecanttoequatoristermedregular,ornormal.Whenthecylinderistangenttothespherecontactisalongagreatcircle(thecircleformedonthesurfaceoftheEarthbyaplanepassingthroughthecenteroftheEarth).Inthesecantcase,thecylindertouchesthespherealongtwolines,bothsmallcircles(acircleformedonthesurfaceoftheEarthbyaplanenotpassingthroughthecenteroftheEarth).(切線或割線到赤道被稱為規(guī)則，或正常。當(dāng)氣缸的球體接觸切線沿大圓（圈形成表面的地球的飛機(jī)經(jīng)過克通過地球中心。在割線的情況下，圓柱體沿兩條線接觸球體，兩個球體都是圓的（一個在地球表面上形成的圓，而不是通過雖然地球的中心）。)●Tangentorsecanttoameridianisthetransverseaspect.Whenthecylinderuponwhichthesphereisprojectedisatrightanglestothepoles,thecylinderandresultingprojectionaretransverse.(子午線的切線或割線是橫切面。當(dāng)球體被投射的圓柱體與兩極成直角時，圓柱體和由此產(chǎn)生的投影是橫向的。)●Tangentorsecanttoanotherpointontheglobeiscalledoblique.Whenthecylinderisatsomeother,non-orthogonal,anglewithrespecttothepoles,thecylinderandresultingprojectionisoblique.(切線或割線到地球上的另一個點稱為斜。當(dāng)氣缸在ME，非正交的，相對于極角，氣缸和投影是義務(wù)神游。)Conicprojectionsresultfromprojectingasphericalsurfaceontoacone.Whentheconeistangenttothespherecontactisalongasmallcircle.Inthesecantcase,theconetouchesthespherealongtwolines,oneagreatcircle,theotherasmallcircle.IntheConicalProjectionthegraticuleisprojectedontoaconetangent,orsecant,totheglobealonganysmallcircle(usuallyamid-latitudeparallel).Inthenormalaspect(whichisobliqueforconicprojections),parallelsareprojectedasconcentricarcsofcircles,andmeridiansareprojectedasstraightlinesradiatingatuniformangularintervalsfromtheapexoftheflattenedcone.Conicprojectionsarenotwidelyusedinmappingbecauseoftheirrelativelysmallzoneofreasonableaccuracy.Thesecantcase,whichproducestwostandardparallels,ismorefrequentlyusedwithconics.Eventhen,thescaleofthemaprapidlybecomesdistortedasdistancefromthecorrectlyrepresentedstandardparallelincreases.Becauseofthisproblem,conicprojectionsarebestsuitedformapsofmid-latituderegions,especiallythoseelongatedinaneast-westdirection.TheUnitedStatesmeetsthesequalificationsandthereforeisfrequentlymappedonconicprojections.(球面投影到圓錐上的圓錐投影結(jié)果。當(dāng)圓錐體與球面相切時，接觸點是一個小圓圈。在割線的情況下，圓錐體接觸球體翁兩行，一一大圈，另一小圈。在圓錐投影的經(jīng)緯網(wǎng)投影到圓錐切線或割線，在小繞地球（通常是一個mid-l緯度平行）。在不平行的方面（斜向圓錐投影），平行線被投影為圓的同心圓弧，子午線被投影為直線在平錐頂點上均勻的角距，由于其相對合理的精度范圍較小，圓錐映射在制圖中的應(yīng)用并不廣泛。割線的情況下生產(chǎn)雙標(biāo)準(zhǔn)緯線，更頻繁地使用圓錐曲線。即使這樣，地圖的規(guī)模迅速變得扭曲，從正確的表示標(biāo)準(zhǔn)并行增加距離锿.由于這個問題，圓錐投影最適合中緯度地區(qū)的地圖，特別是那些在東西方向拉長的地圖。美國滿足這些資格ND經(jīng)常被映射在圓錐投影。)Azimuthal(Planar)projectionsresultfromprojectingasphericalsurfaceontoaplane.WhentheplaneistangenttothespherecontactisatasinglepointonthesurfaceoftheEarth.Inthesecantcase,theplanetouchesthespherealongasmallcircleiftheplanedoesnotpassthroughthecenteroftheEarth,whenitwilltouchalongagreatcircle.(方位角（平面）投影是將一個球面投影到一個平面上，當(dāng)平面與球面相切時，在地球表面的一個點上。在美國證券交易委員會如果飛機(jī)不穿過地球的中心，當(dāng)它沿著一個大圈旋轉(zhuǎn)時，飛機(jī)就會沿著一個小圓圈接觸球體。)Miscellaneousprojectionsincludeunprojectedonessuchasrectangularlatitudeandlongitudegridsandotherexamplesofthatdonotfallintothecylindrical,conic,orazimuthalcategories.(雜項預(yù)測包括未計劃的如矩形經(jīng)緯網(wǎng)格和其他的例子，不落入圓柱形，圓錐形，或方位的類別。)Choosingaprojectionistodetermine:Location,SizeandShape.Thesethreethingsdeterminewheretheareatobemappedfallsinrelationtothedistortionpatternofanyprojection.One“traditional”ruledescribedbyMaling(Maling,1992)says:(選擇一個投影是阻止我的：位置，大小和形狀。這三件事決定要映射的區(qū)域與任何投影的變形模式有關(guān)。一個“傳統(tǒng)”的規(guī)則描述的Maling（馬嶺，1992）說：)Acountryinthetropicsasksforacylindricalprojection.(熱帶地區(qū)的一個國家需要一個圓柱投影。)Acountryinthetemperatezoneasksforaconicalprojection.(溫帶地區(qū)的國家要求錐形投影。)Apolarareaasksforanazimuthalprojection.(極性區(qū)域要求方位投影。)Implicitintheserulesofthumbisthefactthattheseglobalzonesmapintotheareasineachprojectionwheredistortionislowest:Cylindricalsaretrueattheequatoranddistortionincreasestowardthepoles.Conicsaretruealongsomeparallelsomewherebetweentheequatorandapoleanddistortionincreasesawayfromthisstandard.Azimuthalsaretrueonlyattheircenterpoint,butgenerallydistortionisworstattheedgeofthemap.Foraparticularmap-usethemapmayneedtobeconformal,equalarea,orsomecompromiseofthese.Insomecases,suchasnavigation,conformalityisabsolutelynecessary.Instatisticalmapping,equivalenceisnecessary.Thefinalprojectionchoicewouldseemtobeafairlystraightforwardfunctionofminimizeddistortionandspecialproperties.（在這四MB規(guī)則隱含的事實是，這些全球區(qū)MAP為每個投影在變形區(qū)羅西：cylindricals在赤道向兩極和失真的增加是真實的。圓錐曲線是真實的，我所以我在平行的赤道和極和失真增加的方式從這一標(biāo)準(zhǔn)間。azimuthals是真的只有在他們的中心點，但一般的失真是最嚴(yán)重的在地圖的邊緣。對于一個特定的地圖使用的地圖可能需要是共形，平等的地區(qū)，或一些妥協(xié)。在某些情況下，如導(dǎo)航、協(xié)調(diào)是絕對必要的。在統(tǒng)計映射中，等價是必要的。最后的投影選擇將看到M是一個相當(dāng)直的函數(shù)最小化失真和特殊屬性。）UniversalTransverseMercator(UTM)(通用橫軸墨卡托投影（UTM））Mercatorprojectionwasinventedin1569byGerardusMercator(Flanders)graphically.Thepropertiesofthisprojectionare:(1)Conformal.