专业英语8到11单元翻译

Horizontalandverticalanglesarefundamentalmeasurementsinsurveying.（水平角和竖直角是测量的基本测量工作）Itisnecessarytobefamiliarwiththemeaningsofcertainbasictermsbeforedescribingangleanddirectionmeasurement.（在描述角度和方向测量之前，有必要熟悉几个基本术语的含义）Thetermsdiscussedherehavereferencetotheactualfigureoftheearth.（这里讨论的这些术语与地球的真实形状有关）BasicTerms（基本术语）Averticallineatanypointontheearth’ssurfaceisthelinethatfollowsthedirectionofgravityatthatpoint.（地球表面任一点的垂线是指这点上沿着重力的方向的线）Itisthedirectionthatastringwillassumeifaweightisattachedatthatpointandthestringissuspendedfreelyatthepoint.（如果在这点上用线悬挂一个重物，当线自由静止时，这条线所呈现的方向即重力方向。）Atagivenpointthereisonlyoneverticalline.（在给定的一个点上只有一条垂线。）Ahorizontallineatapointisanylinethatisperpendiculartotheverticallineatthepoint.（一点上的水平线是垂直于过该点的垂线的直线。）Atanypointthereareanunlimitednumberofhorizontallines.（过任一点的水平线有无数条。）Ahorizontalplaneatapointistheplanethatisperpendiculartotheverticallineatthepoint.（过一点的水平面是垂直于过该点的垂线的平面）Thereisonlyonehorizontalplanethroughagivenpoint.（过给定的一个点只有一个水平面）Averticalplaneatapointisanyplanethatcontainstheverticallineatthepoint.（过一点的竖直面是包含过该点的垂线的任一平面）Thereareanunlimitednumberofverticalplanesatagivenpoint.（过给定的一点有无数个竖直面）HorizontalAngleandVerticalAngle（水平角和竖直角）Ahorizontalangleistheangleformedinahorizontalplanebytwointersectingverticalplanes,orahorizontalanglebetweentwolinesistheanglebetweentheprojectionsofthelinesontoahorizontalplane.（水平角是指在一个水平面内由两相交的竖直面形成的角，或者说，两条线之间的水平角是这两条线在水平面上的投影线的夹角）Forexample,observationstodifferentelevationpointsBandCfromAwillgivethehorizontalangle∠bacwhichistheanglebetweentheprojectionsoftwolines(ABandAC)ontothehorizontalplane.（例如，在A点观测不同高度的B和C点，其水平角∠bac是由AB和AC两条线在水平面上的投影构成的）Itfollowsthat,althoughthepointsobservedareatdifferentelevations,itisalwaysthehorizontalangleandnotthespaceanglethatismeasured(Figure1).（由此得出结论，虽然被观测的点在不同的高度上，测出的总是水平角而不是空间角。）Thehorizontalangleisusedprimarilytoobtainrelativedirectiontoasurveycontrolpoint,ortopographicdetailpoints,ortopointstobesetout.（水平角主要用来由联测控制点获得相对方向，或者地形测量碎部点、或者放样点Averticalangleisananglemeasuredinaverticalplanewhichisreferencedtoahorizontallinebyplus(up)orminus(down)angles,ortoaverticallinefromthezenithdirection.（竖直角是在一个竖直面内参考于水平线的正（仰）角或负（俯）角，或者相对于一个天顶方向的垂线的角）Plusandminusverticalanglesaresometimesreferredtoaselevationordepressionangles,respectively.（正负竖直角有时分别被称为仰角或俯角）Averticalanglethusliesbetween0°and±90°.（竖直角位于0～90度之间）Zenithisthetermdescribingpointsonacelestialspherethatisasphereofinfinitelylargeradiuswithitscenteratthecenteroftheearth.（天顶方向是一个术语，用来描述在天球上的点，天球是一个半径无限大的球，其中心在地球中心。）Thezenithisananglemeasuredinaverticalplanedownwardfromanupwarddirectedverticallinethroughtheinstrument.（天顶距是一个在竖直面内从一个过仪器的被定向为向上的竖直方向线向下测量的角。）Itisthusbetween0°and180°.（它的范围是从0到180度）Obviouslythezenithangleisequalto90°minustheverticalangles.（显然，天顶距等于90度减去竖直角）Verticalanglesorzenithsareusedinthecorrectionofslopedistancetothehorizontalorinheightdetermined.（竖直角或天顶距用于斜距化平距的改正或者高程的测量）Forthemostpart,theinstrumentusedinthemeasurementofanglesiscalledatransitortheodolite,althoughanglescanbemeasuredwithclinometers,sextants(hydrographicsurveys),orcompasses.（在极大程度上，用来测角的工具被称为经纬仪，虽然角度可以用倾斜仪、六分仪（用于海道测量）、或罗盘仪来测）Thetheodolitecontainsahorizontalandverticalcirclesofeitherglassorsilver.（经纬仪有一个玻璃的或镀银的水平度盘和竖直度盘）Thehorizontalandverticalcirclesoftheodolitecanbelinkedtocircularprotractorsgraduatedfrom0°to360°inaclockwisemannersetinhorizontalandverticalplane.（经纬仪的水平度盘和竖直度盘与顺时针刻了0到360度刻划的圆分度器相连）Thehorizontalcircleisusedwhenmeasuringorlayingoffhorizontalanglesandtheverticalcircleisusedtomeasureorlayoffverticalanglesorzenithangles.（测或拨水平角时用水平度盘，测或拨竖直角或天顶距时用竖直度盘）Usuallytheunitsofangularmeasurementemployedinpracticearedegrees,minutes,andseconds,thesexagesimalsystem.通常角度测量法（使用的单位是六十进制的度、分、秒）AngleMeasurement（角度测量）Ahorizontalangleinsurveyinghasadirectionorsense;thatis,itismeasuredordesignedtotherightortotheleft,oritisconsideredclockwiseorcounterclockwise.（在测的水平角有方向 ，就是说它是向左测还是向右测，或者是说，顺时针测还是逆时针测）方向Intheabovefigure,theangleatAfromBtoCisclockwiseandtheanglefromCtoBiscounterclockwise.（如上图所示，在A点由B到C就是顺时针角，而从C到B就是逆时针角）Withthetheodolitesetup,centered,andleveledoveratstationA,thenasimplehorizontalanglemeasurementbetweensurveyingpointB,AandCwouldbetakenasfollows:（经纬仪在A点安置、对中、整平后，在B、A和C测量点间的简单的水平角测量可以按下列步骤进行：）⑴Commencingon,say,“faceleft”,thetargetsetatsurveypointBiscarefullybisectedandthereadingonhorizontalscaleis25°.（着手，说“盘左”将B点的目标仔细分中，水平,度盘读数为25度）⑵TheupperplateclampisreleasedandtelescopeisturnedclockwisetosurveypointC.Thereadingonhorizontalcircleis75°（水平度盘制动螺旋松开，顺时针转动望远镜至C点，水平度盘读数75度）⑶Thehorizontalangleisthenthedifferenceofthetwodirections,i.e.(75°-25°)=50°（水平角就是两个方向值的差值，即，(75°-25°)=50°）⑷ChangefaceandobservepointCon“faceright”,andnotethereading=255°（换度盘方向至盘右并照准C点，记下读数为255度）⑸ReleaseupperplateandswingcounterclockwisetopointBandnotethereading=205°（松开水平度盘，逆时针旋转至B点并记下读数为205度）⑹Thereadingorthedirectionmustbesubtractedinthesameorderas255°-205°=50°（读数或者说是方向值按同样的法则相减，255°-205°=50°）⑺Themeanoftwovalueswouldbeacceptediftheyareinacceptableagreement.（如果两个减出来的值的一致性是可接受的，取两个值的平均值。）Modernelectronicdigitaltheodolitescontaincircularencodersthatsensetherotationsofthespindlesandthetelescope,converttheserotationsintohorizontalandvertical(orzenith)angleselectronically,anddisplaythevalueoftheanglesonliquidcrystaldisplays(LCDs)orlight-emittingdiodedisplays(LEDs).（现代的电子数字经纬仪包含编码度盘，能够感知轴和望远镜的旋转，并使之电子地转换为水平角度和竖直角度，并在液晶显示器或发光二极管显示器上显示出来）Thesereadoutscanberecordedinaconventionalfieldbookorcanbestoredinadatacollectorforfutureprintoutorcomputation.（这些显示可以被一个传统的野外电子手簿或数据收集器记录，以便日后打印或计算）Theinstrumentcontainsapendulumcompensatororsomeotherprovisionforindexingtheverticalcirclereadingstoanabsoluteverticaldirection.（这种仪器具有一个悬挂补偿器或其它装置，使竖盘指标读数指向一个绝对竖直方向）Thecirclecanbesettozeroreadingsbyasimplepressofabuttonorinitializedtoanyvalueontheinstrument.（这个度盘可以通过简单的按一个键就将其置零，或初始化成任一值）Azimuthisthehorizontalanglemeasuredinaclockwisedirectionfromtheplaneofthemeridian,whichisalineonthemeansurfaceoftheearthjoiningthenorthandsouthpoles.（方位角是从子午面起算按顺时针旋转的角，子午线是在地球平均表面连接北极与南极的线）Azimuthrangesinmagnitudefrom0°to360°,valuesinexcessof360°,whicharesometimesencounteredincomputations,aresimplyreducedby360°beforefinallisting.（方位角的取值范围从0度到360度，超过360的值――有时会在计算时遇到，只需减去360度即可）Bearingisthetraditionalwayofstatingtheorientationoftheline.（方向角是一种传统的描述直线方向的方法）Itisactuallytheanglemeasuredfromthenorthorsouth.（实际上，它是从南或北方向开始量测的角）Thebearing,whichcanbemeasuredclockwiseorcounterclockwisefromthenorthorsouthendofthemeridian,isalwaysaccompaniedbylettersthatlocatethequadrantinwhichthelinefalls.（方向角可以从子午线北端或南端以顺时针或逆时针量测，总是伴以字母，用来标明直线所落在的象限）Forexample,bearingN32Windicatesalinetrending32°westofthenorth.（例如：方向角N32W代表一条直线从北方向转向西方向32度）Itisequaltoanazimuthof328°.（它等于方位角328度）BearingS12Windicatesalinetrending12°westofthesouth.（方向角S12W代表一条直线从南方向转向西方向12度）Itisequaltoanazimuthof192°.（它等于方位角192度）Itisimportanttostatethatthebearingandazimutharerespecttotruenorth.（需要重点说明的是，方向角和方位角所用的是真北方向。Unit9Traversing（导线测量）Thepurposeofthesurveyingistolocatethepositionsofpointsonornearthesurfaceoftheearth.（测量的目的是确定地表或接近地表的点的点位。）Todeterminehorizontalpositionsofarbitrarypointsontheearth’ssurfaceandelevationofpointsaboveorbelowareferencesurfaceareknownasacontrolsurvey.（确定地表任一点的平面位置和确定点高于或低于一个参考面的高程的工作被称为控制测量）Thepositionsandelevationsofthepointsmakeupacontrolnetwork.（这些点的平面位置和高程组成了一个控制网）Therearedifferenttypesofcontrolnetworksdependingonwhereandwhytheyareestablished.（依照它们建立的地点和目的不同，有不同的控制网类型）Acontrolnetworkmayhaveveryaccuratepositionsbutnoelevations(calledaHorizontalControlNetwork)orveryaccurateelevationsbutnopositions(calledaVerticalControlNetwork).（一个控制网可能有精确的平面位置而没有高程（称为平面控制网），或者有精确的高程而没有平面位置（称为高程控制网））Somepointsinacontrolnetworkhavebothaccuratepositionsandelevations.（有些控制网的点既有精确的平面位置也有精确的高程）Controlnetworksrangefromsmall,simpleandinexpensivetolargeandcomplexandveryexpensivetoestablish.（控制网的范围从小的、简单的、便宜的网到大的、复杂的、昂贵的网）Acontrolnetworkmaycoverasmallareabyusinga“local”coordinatesystemthatallowsyoutopositionthefeaturesinrelationtothecontrolnetworkbutdoesn’ttellyouwherethefeaturesareonthesurfaceoftheearth,orcoveralargeareabyconsistingofafewwell-placedandprecise-establishedcontrolpoints,whichissometimescalledtheprimarycontrol.（一个控制网可以是覆盖小范围，使用区域坐标系统，允许你相对于控制网确定地貌特征，但却不告诉你它们在地表的什么地方；或者覆盖一个广大区域，由少数被适当安置并精确测设的控制点组成，有时被称为基础控制）Thehorizontalpositionsofpointsinanetworkcanbeobtainedinanumberofdifferentways.（控制网的点的平面位置可以由许多不同方法来获得）Thegenerallyusedmethodsaretriangulation,trilateration,traversing,intersection,resectionandGPS.（一般使用的方法有，三角测量、三边测量、导线测量、交会测量、后方交会测量、和GPS测量）Themaintopicofthistextreferstothetraversing.（这篇课文主要讲的是导线测量）Triangulation（三角测量）Themethodofsurveyingcalledtriangulationisbasedonthetrigonometricpropositionthatifonesideandthreeanglesofatriangleareknown,theremainingsidescanbecomputedbythelawofsines.（这种测量方法称为三角测量，基于三角法则如果三角形的一条边和三个角已知，剩下的边可以用正弦定理计算出）Furthermore,ifthedirectionofonesideisknown,thedirectionoftheremainingsidescanbedetermined.（而且，如果一条边的方向已知，余下的边的方向也可以确定）Andthencoordinatesofunknownpointscanbecomputedbyapplicationoftrigonometry.（那么未知点的坐标就可以使用三角法计算出来）Trilateration（三边测量） Sincetheadventoflong-rangeEDMinstrument,amethodofsurveyingcalledtrilaterationwasadoptedtocombinewithtriangulation.（自从远距EDM出现以来，一种叫做三边测量的方法用来和三角测量联合使用。）Thetrilaterationisbasedonthetrigonometricpropositionthatifthethreesidesofatriangleareknown,thethreeanglescanbecomputedbythelawofcosines.（三边测量基于三角法则——如果三角形的三条边已知，那么三个角可以由余弦定理计算出）TrilaterationpossessessomeadvantagesovertriangulationbecausethemeasurementofthedistanceswithEDMinstrumentissoquick,preciseandeconomicalwhilethemeasurementoftheanglesneededfortriangulationmaybemoredifficultandexpensive.（三边测量具有一些相对于三角测量的优势，EDM测距快速、准确、经济，而三角测量所需的角度测量则相对困难和昂贵）Forsomepreciseprojects,thecombinationoftriangulationandtrilaterationwhichiscalledtriangulaterationisapplied.（在一些精密 工程 路基工程安全技术交底工程项目施工成本控制工程量增项单年度零星工程技术标正投影法基本原理 当中，三角测量和三边测量联合使用，被称为边角测量）Traversing（导线测量）Asurveytraverseisasequenceoflengthsanddirectionsoflinesbetweenpointsontheearth,obtainedbyorfromfieldangleanddistancemeasurementsandusedindeterminingpositionsofthepoint.（导线是一系列地球上点之间的有长度和方向的直线，由野外角度和距离测量获得，用来确定点位）Theanglesaremeasuredusingtransits,theodolites,ortotalstations,whereasthedistancescanbemeasuredusingsteeltapesorEDMinstruments.（角度可以使用经纬仪或全站仪来测，而距离可以使用卷尺或EDM来测）Asurveytraversemaydeterminetherelativepositionsofthepointsthatifconnectsinseries,andiftiedtocontrolstationsbasedonsomecoordinatesystem,thepositionsmaybereferredtothatsystem.（导线可以用来确定互相连接点的相对位置，如果想控制某些坐标系中的站点，其位置应参考该坐标系）Fromthesecomputedrelativepositions,additionaldatacanbemeasuredforlayoutofnewfeatures,suchasbuildingsandroads.（从这些计算出的相对位置，另外的数据可以量出来，用以放样新的地物，如：建筑物和道路。）SincetheadventofEDMequipment,traversinghasemergedasthemostpopularmethodtoestablishcontrolnetworkssuchasbasicareacontrol,mapping,controlofhydrographicsurveysandconstructionprojects.（自从EDM的出现，导线测量作为最常用的建立控制网的方法显现出来，例如基础区域控制、图根控制、水道测量控制和建筑工程控制）Inengineeringsurveying,itisidealwaytosurveysanddimensionalcontrolofroute-typeprojectssuchashighway,railroad,andpipelineconstruction.（在工程测量当中，导线测量是线型工程测量和立体控制的理想方法，线型工程例如公路、铁路、和管线建筑）Ingeneral,atraverseisalwaysclassifiedaseitheranopentraverseoraclosedtraverse.（总体上，导线总是分为支导线和闭路导线）Anopentraverseoriginateseitheratapointofknownhorizontalpositionwithrespecttoahorizontaldatumoratanassumedhorizontalposition,andterminatesatastationwhoserelativepositionisnotpreviouslyknown.（支导线起始于一个水平位置已知（相对于一个水平基准）或水平位置假定的点，终止于事先未知的站点。）Theopentraverseprovidesnocheckagainstmistakesandlargeerrorsforitsterminationatanunknownhorizontalpositionandlackofgeometricclosure.（由于其终点位置未知并且缺乏图形闭合，支导线不能提供对错误和较大误差的检核）Thislackofgeometricclosuremeansthatthereisnogeometricverificationpossiblewithrespecttotheactualpositioningofthetraversestations.（这种图形闭合的缺少意味着没有几何上的检核可能性，对于实际的导线点的确定。）Thus,themeasuringtechniquemustberefinedtoprovideforfieldverification.（因而，这种测量技术应当提供野外的检核使之精确）。Ataminimum,distancesaremeasuredtwiceandanglesaredoubled.（至少，距离测两遍，角度测两个测回。）Opentraversesareoftenusedforpreliminarysurveyforaroadorrailroad.（支导线经常用于道路或铁路的初测）Aclosedtraversecanbedescribedinanyoneofthefollowingtwoways:（闭路导线可以由下面两种方式的任一种描述：）⑴Aclosedlooptraverse,asthenameimplies,formsacontinuousloop,enclosinganarea.（闭合环路导线，正如名字所示，呈一个连续的环，围绕一个区域）Thistypeofclosedtraversestartsatassumedhorizontalpositionorataknownhorizontalpositionwithrespecttoahorizontaldatumandendsatthesamepoint.（这种闭路导线起始于一个平面位置假设或相对于一个水平基准已知的点，并终止于该点）⑵Aconnectingtraversestartsandendsatseparatepoints,whoserelativepositionshavebeendeterminedbyasurveyofequalorhigherorderaccuracy.（附合导线起始和终止于不同的点，它们由等于或高于规定精度的测量测设）Aknownhorizontalpositionisdefinedbyitsgeographiclatitudeandlongitude,orbyitsXandYcoordinatesonagridsystem.（一个已知的水平位置是由它的大地经纬度或格网系的XY坐标表示）Closedtraverses,whethertheyreturntothestartingpointornot,providechecksonthemeasuredanglesanddistances.（闭合导线，无论它们是否回到起始点，都能提供角度和距离检核。）Inbothcases,theanglescanbeclosedgeometrically,andthepositionclosurecanbedeterminedmathematically.（在两种情况中，角度可以在几何上闭合，位置闭合可以数学的确定）Thereforetheyaremoredesirableandusedextensivelyincontrol,construction,property,andtopographicsurveys.（因此它们更理想，在控制测量、建筑测量、房地产测量和地形测量使用更广泛）Aswementionedabove,aclosedtraverseprovideschecksonthemeasuredanglesanddistances.（正如我们上面所提到的，闭合导线可以提供角度和距离的检核）Forexample,thegeometricsumoftheinterioranglesinann-sideclosedfigureshouldbe(n-2)×180°,butduetosystematicandrandomerrorsofthemeasurements,whenalltheinterioranglesofaclosedtraversearesummed,theymayormaynottotalthenumberofdegreesrequiredforgeometricclosure.（例如，在一个n边闭合图形当中，内角和应该是：(n-2)×180°，但是由于测量中系统误差和偶然误差的存在，当闭合导线所有的内角加起来后，其角度和可能等于或不等于其几何理论闭合差值）Thedifferencebetweenthegeometricsumandactualfieldsumoftheinterioranglesiscalledangularclosure.（内角和的理论值和实际值的差值被称为角度闭合差）Thetotalerrorofangularclosureshouldbedistributedevenlytoeachangle(ifallanglesweremeasuredwiththesameprecision)beforemathematicalanalysisofthetraverse.（在导线进行数学 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 之前，角度闭合差应该平均分配到每个角上（如果所有的角都是相同观测精度））Theimportantpointbeforedoingthisisthattheoverallangularclosurecan’tbebeyondthesurveyspecifications.（重要的一点是，在这样做之前，所有的闭合差都不得超过测量规范 ）Closedtraversesprovidealsochecksonthemeasureddistances,andthepositionclosurecanbedeterminedmathematically,whichmeansthatanindicationoftheconsistencyofmeasuringdistancesaswellasanglesshouldbegiventoatraversethatclosesonitself.（闭合导线同时提供测量过的距离的检核，位置的闭合差可以计算得到，这就意味着测量的距离同测角一样，应当予以闭合）Theoreticallythispositionclosurefromtheoriginbacktoitselfshouldbezero.（理论上，从起点闭合到它自己，位置的闭合差应该是0）ButtheErrorsinthemeasureddistancesandanglesofthetraverses,however,willtendtoaltertheshapeofthetraverse,thereforeweshouldcomputethealgebraicsumofthelatitudesandalgebraicsumofthedepartures,andcomparethemwiththefixedlatitudeanddepartureofastraightlinefromtheorigintotheclosingpoint.（但是距离和角度的测量误差，会改变导线的形状，因此我们应当分别计算纵距与横距的代数和，然后与从起点到终点的连线的确定的纵距与横距相比较）Bydefinition,latitudehereisthenorth/southrectangularcomponentofalineanddepartureistheeast/westrectangularcomponentofaline.（精确的说，这里的纵距就是指一条直线的直角坐标的南北分量，横距就是指一条直线的直角坐标的东西分量）Todifferentiatedirection,northisconsideredplus,whereassouthisconsideredminus.（对于不同的方向来说，北方向为正，南方向为负）Similarly,eastisconsideredplus,whereaswestisconsideredminus.（同样的，东为正，西为负）Thenthediscrepancyshouldbeadjustedbyapportioningtheclosurebothinlatitudesandindeparturesonareasonablebasis.（然后差值应以合理的原则进行调整分配闭合差到纵距和横距上去）Theadjustedpositionofeachtraversepointisdeterminedwithrespecttosomeorigin.（ThispositionisdefinedbyitsYcoordinatesanditsXcoordinateswithrespecttoaplanerectangularcoordinatesysteminwhichtheYaxisisassumednorth-southwhereastheXaxiseast-west.（其位置由平面直角坐标系的Y坐标和X坐标来定义，轴代表YX轴代表东西方向）Unit10MethodsofElevationDetermination（高程测量方法）Anelevationisaverticaldistanceaboveorbelowareferencedatum.（高程是高于或低于一个参考基准的一个垂直距离。）Althoughverticaldistancecanbereferencedtoanydatum,insurveying,thereferencedatumthatisuniversallyemployedisthatofmeansealevel(MSL).（虽然垂直距离可以参考任何一个基准，但是在测量上，这个参考基准一般使用的是平均海平面（MSL））MSLisassignedaverticalvalue(elevation)of0.000ftor0.000m.（MSL被赋予一个0.000英尺或0.000米的高程）Allotherpointsontheearthcanbedescribedbytheelevationsaboveorbelowzero.（地球上所有其它点可以用高于或低于0的高程来描述）Permanentpointswhoseelevationshavebeenpreciselydetermined(benchmarks)areavailableinmostareasforsurveyuse.（高程精确测出的永久点（水准点）被用于大多数区域的测量工作）InChina,7yearsofobservationsattidalstationsinQingdaofrom1950to1956werereducedandadjustedtoprovidetheHuanghaiverticaldatumof1956.（在中国，利用青岛验潮站从1950年到1956年7年的观测数据处理和平差，建立了56黄海高程系统）Inthe1987,thisdatumwasfurtherrefinedtoreflectlongperiodicaloceantidechangetoprovideanewnationalverticaldatumof1985,accordingtotheobservationsattidalstationsfrom1952to1979.（1987年，在依照了验潮站1952到1979年的观测资料后，这个基准被进一步精确——反映长时期海潮变化的85国家高程基准建立起来。）Although,strictlyspeaking,thenationalverticaldatummaynotpreciselyagreewiththeMSLatspecificpointsontheearth’ssurface,thetermMSLisgenerallyusedtodescribethedatum.（虽然，严格说来，国家高程基准在特殊的点上与MSL并不恰好吻合，术语MSL一般还是用来描述它）MSLisassignedaverticalvalue(elevation)of0.000ftor0.000m.（MSL高程的赋值为0.000英尺或米）Differenceinelevationmaybemeasuredbythefollowingmethods:(JamesM.AndersonandEdwardM.Mikhail.1998)（高程的差异可以由下列方法测得（詹姆斯.安德森和爱德华.？？？））1.Directorspiritleveling,bymeasuringverticaldistancesdirectly.（水准测量，直接测得垂直距离）Directlevelingismostprecisemethodofdeterminingelevationsandtheonecommonlyused.（水准测量是高程测量方法中精度最高、使用最普遍的方法）2.Indirectortrigonometricleveling,bymeasuringverticalanglesandhorizontalorslopedistances.（三角高程测量，利用测量竖直角和水平或斜距来测高程）3.Stadialeveling,inwhichverticaldistancesaredeterminedbytacheometryusingengineer’stransitandlevelrod;plane-tableandalidadeandlevelrod;orself-reducingtacheometerandlevelrod.（视距高程测量，利用视距测量，使用工程经纬仪和水准尺；平板仪和照准仪和水准尺；或者自处理视距仪和水准尺测得垂直距离）4.Barometricleveling,bymeasuringthedifferencesinatmosphericpressureatvariousstationsbymeansofabarometer.（气压水准测量，通过使用气压计测量不同站点大气压力的差值来测高程）5.Gravimetricleveling,bymeasuringthedifferencesingravityatvariousstationsbymeansofagravimeterforgeodeticpurposes.（重力水准测量，通过使用重力计测量不同站点的重力值差值来测高程，用于大地测量学的目的）6.Inertialpositioningsystem,inwhichaninertialplatformhastreemutuallyperpendicularaxes,oneofwhichis“up”,sothatthesystemyieldselevationasoneoftheoutputs.（惯性定位系统，含有一个惯性平台，具有三个互相垂直轴，其中一个是“向上”的，所以这个系统产生的输出其中一个就是高程。）Verticalaccuraciesfrom15to50cmindistancesof60and100km,respectively,havebeenreported.（各自地，据相关 报告 软件系统测试报告下载sgs报告如何下载关于路面塌陷情况报告535n,sgs报告怎么下载竣工报告下载 ，在60和100km的距离上，其精度能达到15到50cm）Theequipmentcostisextremelyhighandapplicationsarerestrictedtoverylargeprojectswhereterrain,weather,time,andaccessimposespecialconstraintsontraditionalmethods.（这种装置成本极只限于高，非常大的项目，这些项目地质、气象、授时、以及？？施加特殊限制在传统方法上）7.GPSsurveyelevationsarereferencedtotheellipsoidbutcanbecorrectedtothedatumifasufficientnumberofpointswithdatumelevationsarelocatedintheregionsurveyed.（GPS高程测量，它的参考面是地球椭球面，但是如果在测区有充分的高程点，可以修正至高程基准上来）Standarddeviationsinelevationdifferencesof0.053to0.094marepossibleundertheseconditions.（在这种情况下，其高差的 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 差能够达到0.053到0.094米。Owingtorefraction,actuallythelineofsightisslightlycurved,theeffectsofcurvatureandrefractionforthehorizontaldistancecanbereducedtoanegligibleamountandnocorrectionforcurvatureandrefractionisnecessaryifbacksightandforesightdistancesarebalancedinpracticaloperation.（由于大气折光的缘故，实际上视线是有些弯曲的，曲率和折光的影响可以被当作可忽略的不必值，加入球气改正，如果在实际工作中后视距和前视距是相等的）TrigonometricLeveling（三角高程测量）Trigonometriclevelingisusedwheredifficultterrain,suchasmountainousareas,precludestheuseofconventionaldifferentialleveling.（三角高程测量适用于困难地形，例如在山区，不能使用常规的微差水准测量。）Themodernapproachistomeasuretheslopedistanceandverticalangletothepointinquestion.（现代的三角高程测量方法是测量到未知点的斜距和垂直角）Slopedistanceismeasuredusingelectromagneticdistancemeasurersandthevertical(orzenith)angleusingatheodolite,orthetotalstationthatintegratethesetwoinstrumentsintoasingleinstrument.（斜距由电磁波测距仪测得，垂直角（或天顶距）由经纬仪测得，或者利用整合了这两种仪器为一体的全站仪来测）Totalstationscontainbuilt-inmicroprocessorsthatcalculateanddisplaythehorizontaldistancefromthemeasuredslopedistanceandverticalheight.（全站仪包含了内置的微处理器，用来根据测得的斜距和垂直角计算和显示水平距离）Thislatterfacilityhasresultedintrigonometricallevelingbeingusedforawidevarietyofheightingprocedures,includingcontouring.（这种后来的设备导致了三角高程测量被广泛用于多种高度测量工作，包括测绘等高线ThebasicconceptoftrigonometricallevelingcanbeseenfromFigure2.（三角高程测量的基本原理可以看图2）WhenmeasuringtheverticalangleαandthehorizontaldistanceSisused,thenthedifferenceinelevationhABbetweengroundpointsAandBistherefore:（当我们用α和S分别表示垂直角和水平距离时，A点和B点之间的高差为：）hAB=S×tanαi–vwhereiistheverticalheightofthemeasuringcenteroftheinstrumentaboveAandvistheverticalheightofthecenterofthetargetaboveB.（i是A点上仪器中心的高度，v是B点上目标中心的垂直高度）Theverticalanglesarepositiveforanglesofelevationandnegativeforanglesofdepression.（垂直角