第5篇traversing.pptVIP

Unit 5 Traversing 一、教学目的 通过教学互动使学生掌握专业词汇并能独立翻译课文。 二、教学要求 通过本章的学习，学生掌握课文相关的专业词汇，并理解课文。 5.1 Vocabulary Traverse Traversing Traverse leg/point/ angle Open traverse Closed traverse Connecting traverse Angle closing error of traverse Total length closing error of traverse Closing error in coordinate increment Survey specifications, specifications of surveys 5.2 Translation of the text A control network may cover a small area by using a “local” coordinate system that allows you to position the features in relation to the control network but doesn’t tell you where the features are on the surface of the earth, or cover a large area by consisting of a few well-placed and precise-established control points, which is sometimes called the primary control. 控制网可能覆盖一块小区域，这种网采用地方坐标系，可用来相对此控制网的地物定位，但不能说明地物在地球的什么位置；也可能通过联测一些选位好且精度高的控制点覆盖一块大范围，常常称为首级控制。 Possess economical Sequence Whereas Ideal Originate Datum Verification Refine Desirable extensively A survey traverse is a sequence of lengths and directions of lines between points on the earth, obtained by or from field angle and distance measurements and used in determining positions of the points. 测量导线是地球上点之间一系列边长和方向，这些边长和方向是由外业角度和距离测量得到，用于确定点的位置。 A survey traverse may determine the relative positions of the points that it connects in series, and if tied to control stations based on some coordinate system, the positions may be referred to that system. 测量导线可以确定连接在导线中的点的相对位置，如果联测到基于某坐标系的控制点上，那么这个位置就是基于该坐标系统的。 Interior Total Distribute Evenly Rectangular Component Differentiate Closed traverses provide also checks on the measured distances, and the position closure can be determined mathematically, which means that an indication of the consistency of measuring distances as well as angles should be given to a traverse that closes on itself. 闭合导线也提供距离检核，位置闭合差可以精确地确定，和角度对于闭合于本身的导线一样，这意味着测距的一致性指标。 But the errors in the measured distances and angles of the traverses, however, will tend to alter the s