Unit 4 Angle and Direction

1、Unit 4 Angle and DirectionMeasurementContentsI Basic termsII Horizontal angle and vertical angleIII Angle measurementBasic TermsVertical line A vertical line at any point on the earths surface is the line that follows the direction of gravity at that point.地球表面任一点的垂线是指这点上沿着重力的方向的线【可译为：地球表面任一点的垂线方向是过

2、该点的重力方向】）The direction of gravityIt is the direction that a string will assume if a weight is attached at that point and the string is suspended freely at the point.（如果在这点上用线悬挂一个重物，当线自由【即无干扰】静止【suspended暂停的、悬浮的】时，这条线所呈现【assume呈现】的方向即重力方向。）Note: At a given point there is only one vertical line. （在给定的

3、一个点上只有一条垂线。）Horizontal lineA horizontal line at a point is any line that is perpendicular to the vertical line at the point. （一点上的水平线是垂直【perpendicular垂直的】于过该点的垂线的直线。） Note: At any point there are an unlimited number of horizontal lines. （过任一点的水平线有无数【unlimited】条。）Horizontal planeA horizontal plane at

4、 a point is the plane that is perpendicular to the vertical line at the point. （过一点的水平面是垂直于过该点的垂线的平面）Note: There is only one horizontal plane through a given point. （过给定的一个点只有一个水平面）Vertical planeA vertical plane at a point is any plane that contains the vertical line at the point. （过一点的竖直面是包含【contai

5、n】过该点的垂线的任一平面）Note: There are an unlimited number of vertical planes at a given point. （过给定的一点有无数个竖直面） Horizontal Angle and Vertical Angle（水平角和竖直角）（水平角和竖直角）Horizontal angleVertical angleThe Zenith天顶距Horizontal anglelDefinitionlA horizontal angle is the angle formed in a horizontal plane by two inter

6、secting vertical planes, or a horizontal angle between two lines is the angle between the projections of the lines onto a horizontal plane. （水平角是指在一个水平面内由两相交【intersect相交v.】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）Example of page 16 For example, observations to different elevation points B and C from

7、A will give the horizontal angle bac which is the angle between the projections of two lines (AB and AC) onto the horizontal plane.（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）FunctionThe horizontal angle is used primarily to obtain relative direction to a survey control point, or topographic det

8、ail points, or to points to be set out. （水平角主要【primarily】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【or to points to be set out应该是or points to be set out才对吧？direction to a survey control point、topographic detail points、points to be set out并列都是obtain的宾语。】）Vertical AngleA vertical angle is an angle in a vertical p

9、lane which referenced to a horizontal line by plus or minus angles, or to a vertical line from the zenith direction. （竖直角是在一个竖直面内参考于【reference参考】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）Plus and minus vertical anglesPlus and minus vertical angles are sometimes referred to as elevation or depression angles.正

10、负竖直角有时分别【respectively分别地】被称为仰角【elevation angle】或俯角【depression angle】）A vertical angle thus lies between 0and 90. （竖直角位于【lie位于】0 90度之间）The ZenithZenith is the term describing points on a celestial sphere that is a sphere of infinitely large radius with its center at the center of the earth. （天顶方向是一个术

11、语，用来描述在天球【celestial sphere天球】上的点，天球是一个半径无限【infinitely无限地】大的球，其中心在地球中心。）The zenith is an angle measured in a vertical plane downward from an upward directed vertical line through the instrument. （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。）The range and function of the zenithIt is between 0 and 180. （它的范围

12、是从0到180度）The zenith angle is equal to 90 minus the vertical angles. （显然，天顶距等于90度减去竖直角）Vertical angles or zeniths are used in the correction of slope distance to the horizontal or in height determined.（竖直角或天顶距用于斜距化平距的改正或者高程的测量）一般情况下，经纬仪测量的角度在水平方向的叫水平角，在竖直方向的叫垂直角，垂直角是从测站到目标的方向（测线）与水平面之间的夹角。而天顶距是测线与竖直方

13、向（也就是天顶）的夹角。1996年中华人民共和国工程测量基本术语标准水平角 horizontal angle测站点至两个观测目标方向线垂直投影在水平面上的夹角垂直角 vertical angle观测目标的方向线与水平面间在同一竖直面内的夹角天顶距 zenith distance测站点铅垂线的天顶方向到观测方向线间的夹角测站 observation station观测时设置仪器或接收天线的位置照准点 sighting point观测时仪器照准的目标点Angle MeasurementInstrument for Measuring anglesHow to MeasureAzimuth and

14、BearingInstrument for MeasurementFor the most part, the instrument used in the measurement of angles is called a transit or theodolite, although angles can be measured with clinometers, sextants (hydrographic surveys), or compasses. （在极大程度上【for the most part】，用来测角的工具被称为经纬仪，虽然角度可以用倾斜仪【一种测量物体随时间的倾斜变化和

15、铅垂线随时间变化的仪器】、六分仪（用于海道测量）、或罗盘仪来测）TheodoliteThe theodolite contains a horizontal and vertical circles of either glass or silver. （经纬仪有一个玻璃的或镀银的水平度盘和竖直度盘）The horizontal and vertical circles of theodolite can be linked to circular protractors graduated from 0 to 360 in a clockwise manner set in horizont

16、al and vertical plane. （经纬仪的水平度盘和竖直度盘与顺时针刻【graduate】了0到360度刻划的圆分度器【circular protractor】相连）The units of angular measurement employed in practice are degrees, minutes, and seconds, the sexagesimal system. （通常角度测量法【angular measurement角度测量法】使用的单位是六十进制【sexagesimal六十进制的】的度、分、秒）Circle度盘The horizontal circl

17、e is used when measuring or laying off horizontal angles and the vertical circle is used to measure or lay off vertical angles or zenith angles. （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【lay off翻译为拨、放样的意思】） 度盘 circle (1996年国家标准）装在测角仪器上用以量测角度的圆盘How to Measure angleModern electronic digital theodolites contain c

18、ircular encoders that sense the rotations of the spindles and the telescope, convert these rotations into horizontal and vertical (or zenith) angles electronically, and display the value of the angles on LCDs or LEDs. （现代的电子数字经纬仪包含编码【encoder编码】度盘，能够感知轴【spindle轴、纺锤】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【

19、LCDs】或发光二极管显示器【LEDs】上显示出来）These readouts can be recorded in a conventional field book or can be stored in a data collector for future printout or computation. （这些显示可以被一个传统的【conventional】野外电子手簿或数据收集器【存储卡】记录，以便日后打印或计算）The instrument contains a pendulum compensator or some other provision for indexing

20、the vertical circle readings to an absolute vertical direction. （这种仪器具有一个悬挂【pendulum钟摆】补偿器【compensator】或其它装置，使竖盘指标【indexing指标】读数指向一个绝对竖直方向）The circle can be set to zero readings by simple press of a button or initialized to any value on the instrument. （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）Azimuth and Bear

21、ingAzimuth is the horizontal angle measured in a clockwise direction from the plane of the meridian. Note: Meridian is a line on the mean surface of the earth joining the north and south poles. （方位角是从子午面【plane of the meridian 】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）uAzimuth ranges in magnitude from 0 to 36

22、0.方位角的取值范围从0度到360度方位角 Azimuth (1996国家标准）通过测站的子午线与测线间顺时针方向的水平夹角Bearing is the traditional way of stating the orientation of the line. It is actually the angle measured from the north or south. （方向角是一种传统的描述【state说明】直线方向【orientation方向、方位】的方法）（实际上，它是从南或北方向开始量测的角）The bearing, which can be measured clockwise or counterclockwise from the north or