highwaysurveymethod

英译汉HighwaySurveyMethodsHighwaysurveysusuallyinvolvemeasuringandcomputinghorizontalandverticalangles,verticalheights(elevations),andhorizontaldistances.Thesurveysarethenusedtopreparebasemapswithcontourlines(thatis,linesonamapconnectingpointsthathavethesameelevation)andlongitudinalcross-sections.Highwaysurveyingtechniqueshavebeenrevolutionizedduetotherapiddevelopmentofelectronicequipmentandcomputers.Surveyingtechniquescanbegroupedintothreegeneralcategories:groundsurveys,remotesensingandcomputergraphics.公路勘测通常包括测量和计算水平角，垂直角，垂直高度（海拔高度）和水平距离。然后测量数据被用来准备并绘制含有等高线（即地形图上高程相等的连结点组成的闭合曲线）和纵向截面的基本图。由于电子设备和计算机的快速发展，公路勘测技术有了革命性的发展。测量技术可以被分为三大类：地面勘测，遥感和计算机绘图。1.GroundsurveysGroundsurveysarethebasiclocationtechniqueforhighways.Thetotalstationisusedformeasuringanglesinbothverticalandhorizontalplanes,distances,andchangesinelevationthroughtheuseoftrigonometriclevels;thelevelisusedformeasuringchangesinelevationonly.Asummaryofsurveyequipmentfollows.地面测量是基本的道路选址技术。使用全站仪测量斜面与平面的角度、测量距离以及使用三角函数得到高度的变化。此函数只能用于测量高度的变化。以下为勘测仪器的总结。1.1TheTotalStationAtotalstationisbothanelectronictheodoliteandelectronicdistance-measuringdevice(EDM).Thetotalstationenablesonetodetermineanglesanddistancesfromtheinstrumenttootherpoints.Anglesanddistancesmaybeusedtocalculatetheactualpositions(coordinatesandelevations).一台全站仪既是电子经纬仪又是电子测距装置。它可以使人们能够从仪器到另一点确定角度和距离，角度和距离可以用来计算实际的位置（坐标和高程）。Thestandardtheodoliteconsistofatelescopewithverticalandhorizontalcrosshairs,agraduatedarcorvernierforreadingverticalangles,andagraduatedcircularplateforreadinghorizontalangles,whereastheelectronictheodoliteprovidesadigitalreadoutofthoseangles.Thesereadoutsarecontinuous,soanglescanbecheckedatanytime.Thetelescopeonbothinstrumentsismountedsothatitcanrotateverticallyaboutahorizontalaxis.Withthestandardtheodolite,twoverticalarmssupportthetelescopeonitshorizontalaxis,withthegraduatedarcattachedtooneofthearms.Thearmsareattachedtoacircularplate,whichcanrotatehorizontallywithreferencetothegraduatedcircularplate,therebyprovidingameansformeasuringhorizontalangles.标准的经纬仪由一个配有竖直和水平制动螺旋的望远镜，一个竖直度盘（刻度弧或游标），以及一个圆形水平度盘。而电子经纬仪则提供角度的电子读数，并且能持续读数以便随时查看角度值。二者都配有悬挂着的望远镜以便其能绕着横轴竖直转动。标准经纬仪两个竖直臂将望远镜支撑于其水平轴上，其中一竖直臂装有刻度弧。两个竖直臂连接在一个能够根据圆形刻度盘水平转动的基座圆盘上，以此测量水平角。1.2ElectronicDistance-MeasuringDevices(EDM)AnEDMdeviceconsistsmainlyofatransmitterlocatedatoneendofthedistancetobemeasuredandareflectorattheotherend.Thetransmittersendsalightbeamoralow-powerlaserpulsewhichisreflectedbacktothetransmitter.Thedifferenceinphasebetweenthetransmittedandreflectedpulsesismeasuredelectronicallyandusedtodeterminethedistancebetweenthetransmitterandthereflector.Thisequipmentcanmeasuredistancesuptoabout1,000metersinaverageatmosphericconditions.Specialfeaturespermittheoperatortochangethedisplayfromslopetohorizontaldistanceautomatically.Unitscanalsobechangedfrommeterstofeet.Thetotalstationoffersthesesolutionsbecauseofinternalinstantaneouscalculations.1.2电子测距仪（EDM）电子测距仪主要是由一个位于测量距离一端的发射器和另一端的反射器组成。发射器发射一个光束或低功率激光脉冲，然后被反射回来。发射和反射的脉冲相位差就会被电子测量，并用来确定发射器和反射器之间的距离。该设备可测量的距离能达到平均大气条件下约1000米。其特殊的功能可以允许操作者自动改变显示器从斜坡到水平的距离。距离单位也可以从米变化到英尺。全站仪之所以能够提供这些功能，是因为其内部的瞬时计算。（张晗，龙飞宇）Figure1IllustrationofHorizontalAngleMeasurementofHorizontalAngles.Ahorizontalangle,suchasangleXOYinFigure1,canbemeasuredbysettingthetheodoliteortotalstationdirectlyoverthepointO.ThetelescopeisthenturnedtowardpointXandviewedfirstoveritstopandthenbysightingthroughthetelescopetoobtainasightlineofOX,usingthehorizontaltangentscrewsprovided.Thegraduatedhorizontalscaleisthensettozeroandlockedintoposition,usingtheclampscrewsprovided.ThetelescopeisrotatedinthehorizontalplaneuntilthelineofsightisOY.Thehorizontalangle(α)isreadfromthegraduatedscale.Whilesimilarinmethodtotheodolite,whenusingatotalstation,theanglemeasuredisshowninadigitalreadoutwhenahorizontalreadoutisselected.水平角度的测量。测量一个像图1中XOY一样的水平角度可以通过设置一个经纬仪或者全站仪在O点上，把望远镜调到对准X点的位置并且首先在它的顶端观察，然后从望远镜里观测并且通过使用水平切线螺旋获得一条OX视线。水平角度值α就显现在了累进刻度上。使用全站仪的方法与此类似，当使用一台全站仪的时候，固定好水平读出器，测量的角度值会显现在一个读数器上。Figure2IllustrationofVerticalAngleMeasurementofVerticalAngles.Thetheodolitemeasuresverticalangles,suchasangleAOBinFigure2byusingthefixedverticalgraduatedarcorvernierandaspiritlevelattachedtothetelescope.Whenatheodoliteisusedtodeterminetheverticalangletoapoint,theangle(β)obtainedistheangleofelevationortheangleofdepressionfromthehorizontal.Thetheodoliteissetupinawaysimilartothatformeasuringhorizontalangles,ensuringthatthelongitudinalaxisisinthehorizontalposition.Thetelescopeisapproximatelysightedatthepoint.Thetangentscrewofthetelescopeisthenusedtosetthehorizontalcrosshairatthepoint.Theverticalangleisobtainedfromthegraduatedarcortheverticalvernier.Again,whilesimilarinmethodtoatheodolite,whenusingatotalstation,theanglemeasuredisshowninadigitalreadoutwhenaverticalreadoutisselected.竖直角的测量。经纬仪测量竖直角，例如使用固定的垂直分度弧(竖盘)或者游标尺和望远镜上的水准器测量图2中的角AOB。当使用经纬仪观测一个目标点确定竖直角，角（&）包括仰角和俯角。经纬仪的放置方法和测量水平角时相似，确保纵轴在一水平方位，望远镜大致对准目标点，然后调节望远镜上的微动螺旋使十字丝对准目标点。竖直角从分度弧或垂直游标上获得。另外，与经纬仪类似，当使用全站仪时，选择一个垂直读数，测得的角度将显示在数字读出仪上。1.3TheLevelTheessentialpartsofalevelarethetelescope,withverticaland