Chinese English

A line perpendicular to the FOCAL PLANE of the CAMERA and passing through the emergent nodal point of the LENS SYSTEM. Also called camera axis. See NODAL POINT.

In PHOTOGRAMMETRY, the intersection of the plane of the PHOTOGRAPH with the horizontal plane of the MAP or the plane of reference of the GROUND. Corresponding lines in the PHOTOGRAPH and map planes intersect on the axis of homology. Also called the axis of perspective, or map parallel.

在摄影测量学中，像平面与地图水平面或参考地平面的交线。像平面与地图水平面上相对应的线均在透射轴上相交。也称作平行透视轴(axis of perspective)或图横线(map parallel)。

The line tangent to the surface of a spirit level tube against which the bubble forms, at the centre of the graduated SCALE of the LEVEL, and in the plane of the tube and its centre of curvature. Also called level axis or spirit level axis.

指与水准气泡管面相切的线，处于水准器刻度尺的中央，以及气泡管的平面和其曲率中心处。亦称level axis （水准轴）或spirit level axis（水准器轴）。

A horizontal angle reckoned clockwise from the meridian. The horizontal direction of a celestial point from a terrestrial point, expressed as the angular distance from a reference direction. It is usually measured from 000° at the reference direction clockwise through 360°. An azimuth is often designated as true, magnetic, compass, grid, or relative as the reference direction is true, magnetic, compass, or grid north, or heading, respectively. Unless otherwise specified, the term is generally understood to apply to true azimuth which may be further defined as the arc of the horizon, or the angle at the zenith, between the north part of the celestial meridian or principal vertical circle and a vertical circle, measured from 000° at the north part of the principal vertical circle clockwise through 360°. When the angle is measured in either direction from north or south, and labelled accordingly, it is properly called azimuth angle; when measured either direction from east or west, and labeled accordingly, it is called AMPLITUDE.

由子午圈按顺时针方向推算出的地平角度。自地面点到一个天体点的地平方向，表示为由基准方向起算的角距离。方位角的测量通常是从基准方向000°开始按顺时针360°进行。如果基准方向是真北方向、磁方向、罗经方向或坐标北方向，或航向方位，则通常分别称之为真方位角、磁方位角、罗经方位角、坐标或相对方位角。除非另有规定，该术语一般都被理解为真方位角，而真方位角可进一步定义为天球子午圈或卯酉圈与垂直圈之间的地平弧或天顶角，按顺时针方向360°自子午圈的北部000°开始量算。该角从南部方向或北部方向进行测量以及做相应的标记时，均可称之为方位角；当从东部方向或者是从西部方向对其进行测量及做相应的标记时，则被称天体出没方位角。

The angle between the observer's MERIDIAN and the VERTICAL CIRCLE through the body, measured in the plane of the HORIZON. There is no universally accepted manner of reckoning the AZIMUTHS. Quadrantal, half-circle, and whole-circle methods are being used. In the latter, the AZIMUTH is measured preferably clockwise from north. See also AZIMUTH ANGLE.

观测者子午圈与过天体的垂直圈之间的夹角。该角是在水平的平面上进行测量。计算方位角尚无一种通用的方法。目前采用的方法有象限法、半圈法和圆周法。在圆周法中最好从北点起按顺时针方向测量。

The angle between the astronomic meridian plane of the observer and the plane containing the observed point and the VERTICAL of the observer.

An AZIMUTH 180° from a given AZIMUTH. In GEODESY, the DIRECTION of the line BA as distinguished from the forward azimuth AB. The two differ by 180° plus the amount of CONVERGENCE OF THE MERIDIANS between points A and B. Also called reverse azimuth. See AZIMUTH: GEODETIC.

指定方位角旋转180度得到的方位角。在大地测量中，BA线的方向不同于AB线的方向。二者相差180°加上AB两点的子午线收敛角。也叫reverse azimuth（反方位角）。参见geodetic azimuth（大地方位角）。

For the GEODESIC LINE from A to B, the angle between the tangent to the MERIDIAN at A and the tangent to the GEODESIC LINE at A. This AZIMUTH is called the forward azimuth for the line AB. See AZIMUTH: BACK.

指对于从A点到B点的大地线，A点的子午线的切线和A点大地线切线的夹角。该方位角可称之为AB线的前方位角。参见back azimuth（反方位角）。

At the point of OBSERVATION, the angle between the VERTICAL PLANE through the observed object and the VERTICAL PLANE in which a freely suspended symmetrically magnetized NEEDLE, influenced by no transient artificial magnetic disturbance, will come to rest.

在观测点，过观测目标的铅垂面与无瞬变人工磁扰影响下自由悬挂且均匀磁化的针逐渐静止时所处的铅垂面之间的夹角。