Chinese English

In PHOTOGRAPHY, the actual difference in DENSITY between the highlights and the shadows on a NEGATIVE or POSITIVE. Contrast is not concerned with the magnitude of DENSITY but only with the difference in DENSITIES. Also the rating of a photographic material corresponding to the relative density difference which it exhibits.

在摄影测量中，正片或负片上最大密度和最小密度之差。它与密度大小无关，而仅与密度差有关。摄影材料对应的相对密度差能够反映材料性能。

A system of points with established POSITIONS or ELEVATIONS, or both, which are used as fixed references in positioning and correlating map features. Control is generally classified in four orders (with first order denoting highest quality) according to the PRECISION of the methods and instruments used in establishing it, and the ACCURACY of the resultant POSITIONS and ELEVATIONS. Often calledbasic control. Regulation or direction of a machine, electronic equipment, etc.; or the DIAL, knob, switch, etc. for performing this function. The exercise of directing influence over the movements of a craft or missile, with particular reference to changes in direction and SPEED.

（1）已经建立位置或高程的点系统，用来作为确定地图要素的位置及相互关系的固定基准。根据它建立时所使用的方法和仪器的精度以及位置和高程的综合精度一般分为四个等级（一等质量最高）。通常称为基本控制。 （2）指对机器、电子设备等的调节或操控，或者执行这个功能的控制调节盘、旋钮、开关等。 （3）指对飞行器或导弹运动过程施加修正影响的过程，尤其指方向和速度变化的修正。

Points established by subordinate SURVEYS, to relate AERIAL PHOTOGRAPHS used in mapping with the system of GEODETIC CONTROL. The points must be positively photo-identified, that is, the points on the GROUND must be positively correlated with their IMAGES on the PHOTOGRAPHS.

用辅助测量的方法（即把测图用的航空照片与大地控制系统关联起来）建立的控制点。这种点必须能在像片上确切地辨认出来，也就是说必须使这种地面位置与它们在像片上的图像建立联系。

根据地面控制进行定向和缩放的镶嵌图，通常由已纠正的像片拼接而成。亦可参见orthophotomosaic（正射像片镶嵌图），uncontrolled mosaic（无控制点镶嵌图）。

A point on the ground whose position (horizontal and vertical) is used as a base for a dependent survey. Also referred to as control station.- 2. In photogrammetry, any point in a horizontal and vertical control system that is identified on a photograph and used for correlating the data shown on that photograph. More specific terms are photo-control point, picture control point and ground control point.

1.地面上的一点，其位置（水平和垂直位置）为相关测量的基础。也称为控制站。 2.在摄影测量中，指像片上可辨认的、用来把像片上显示的资料连接起来的平面和高程控制点。更进一步的规范术语是：photo-control point（像片控制点）、picture control point （图片控制点）、ground control point（地面控制点）。

In general, mass motions within a fluid resulting in TRANSPORT and mixing of the properties of that fluid. In the ATMOSPHERE, organized internal motions within a LAYER of air, leading to vertical transport of heat, momentum, etc.

通常指流体内部的整体运动，会造成流体属性的传递和混合。 在大气中，在一层空气内发生的内部运动，导致热量、动量的垂直传输。

In OCEANOGRAPHY, a situation whereby waters of different origins come together at a point or, more commonly, along a line known as a convergence line. Along such a line the denser water from one side sinks under the lighter water from the other side. See SINKING.

在海洋学中，不同来源的水汇聚到一处，或汇聚到一个锋面上。沿着这个锋面，一侧密度较大的水下沉到另一侧的密度较小的水下面。参见sinking（下降流）。