自考英语讲座(上) 第64讲:Why Are Maps Drawn with North
日期:2008-02-01 14:54

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Tough
painting—water color—sketch
Local government
Localization
Greece
Mathematics
Base
Footnote
Forehead
philosophy
Commonly—ordinarily
Classic
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Refer to---referee
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In line with—out of line with
Rely on / upon

Lesson EIGHTEEN TEXT B

Why Are Maps Drawn with North at the Top
Now it is hard to visualize a map that does not feature north at the top, but this was not always so.
The oldest known map in the accepted sense of the word was drawn about 3,800 BC, and represents the river Euphrates flowing through northern Mesopotamia, Iraq. This, and others that followed it, were little more than rough sketches of localized features; it was not until many centuries later that the ancient Greeks placed the science of map-making on a sound footing.
At the forefront of the pioneers in the field was the Greek mathematician and philosopher Claudius ptolemaeus (c. AD 90-168), more popularly known to history as ptolemy. The last great scientist of the classical period, he was the first to draw a map that was based on all available knowledge, rather than guess or imagination. Earlier, the Babylonians had attempted to map the world, but they presented it in the form of a flattened disc rather than a sphere, which was the form adopted by ptolemy.
Given the state of knowledge of those times, he got things wrong; for example, his estimate of China and the Atlantic ocean was far from being accurate. Nevertheless, it was a useful effort, and the map remained a work of reference for over a thousand years. In fact, Christopher Columbus used a version of it when he set sail in search of the New World -- which caused him some navigational problems, since ptolemy had calculated wrongly the size of the Atlantic and was unaware that the pacific ocean existed.
The really important thing about ptolemys map was that north was at the top. The reason for this was that he decided to orientate the map in the direction of the pole Star since polaris was the immovable guiding light in which the voyagers of that era placed their trust.
North at the top remained the accepted arrangement until the early Middle Ages, when the Church began to interfere seriously with the advance of science. In accordance with the orders of the Church, maps were still produced in accordance with ptolemys principles -- but now Jerusalem was the central feature, as it was held to be the center of the Christian faith, and east was moved to the top.
These maps are often called T Maps because they show only three continents -- Europe, Asia and Africa -- separated by the T formed by the Mediterranean Sea and the River Nile. From a navigational point of view, they were almost useless.
More accurate maps began to appear in the 14th century, with the spread of trade and increasing reliance on the compass. once again, north assumed its rightful place at the top of maps.

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重点单词
  • footnoten. 脚注,补充说明 vt. 给 ... 作脚注
  • referencen. 参考,出处,参照 n. 推荐人,推荐函 vt. 提
  • sketchn. 素描,草图,概述,梗概 v. 速写,草拟,(简略地
  • sailorn. 海员,水手,扁平的硬边草帽
  • availableadj. 可用的,可得到的,有用的,有效的
  • assumedadj. 假装的;假定的
  • flowingadj. 流动的;平滑的;上涨的 v. 流动;起源;上涨
  • roughadj. 粗糙的,粗略的,粗暴的,艰难的,讨厌的,不适的
  • classicn. 古典作品,杰作,第一流艺术家 adj. 第一流的,
  • interferevi. 妨碍,冲突,干涉