什么是制图学
在地图或航图上用图形表示地球自然面貌的科学和技术。它是一门古老的学科,可上溯到史前时代人们所画的渔猎地区图。巴比伦人把世界画成平的圆盘状,托勒密於2世纪着有地理学八卷集,指出地球是一个圆球,为後人研究奠定了基础。中世纪时,按照托勒密的理论绘制的地图都以耶路撒冷为中心,并把东方画在图的上方。较精确的地图是从14世纪开始的,当时为了航海制成了航图。新大陆发现後,要求制图学采用新技术,特别是采用正确的投影技术。麦卡托使用一种圆柱投影方式,视地球为一圆柱。圆柱投影法具有许多优点,但在高纬度地区常常失真。等高线地图是用线连接同等高度的点来显示地形,以平均海平面来做参考点。现代制图方法大多使用航空照相或卫星雷达作为绘制任何一种地图或航图的基础,用这种方法作出的地球地形图达到前所未有的准确度。透过人造卫星摄影,现已能够绘制月球以及一些行星和它们的卫星的表面图。
cartography
Art and science of representing a geographic area graphically, usually by means of a map or chart. Political, cultural, or other nongeographic features may be superimposed. Ptolemy's eight-volume Geography showed a spherical earth. Medieval European maps followed Ptolemy's guide but placed east at the top of the map. The 14th century saw the development of more accurate maps for use in navigation. The first surviving globe dates from 1492. Discovery of the New World led to new techniques in cartography, notably projection of a curved surface onto a flat surface. Gerardus Mercator used a cylindrical projection; which treats the earth as a cylinder. Cylindrical projections have many advantages, though they cause distortions at high latitudes. Contour maps show relief by connecting points of equal elevation with lines, mean sea level being the reference point. Modern cartography uses aerial photography and satellite radar for a degree of accuracy previously unattainable. Satellites have also made possible the mapping of features of the moon and of several planets and their moons. See also geographic information system, global positioning system.
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野无遗贤是什么意思?
意思是:民间没有被弃置不用的人才。指任人唯贤,人尽其才。成语名字:野无遗贤成语发音:yěwúyíxián成语解释:民间没有被弃置不用的人才。指任人唯贤,人尽其才。成语出处:《尚书大禹漠》:“野无遗贤,万邦咸宁。”成语繁体:野無遺賢感情色彩:褒义成语成语用法:主谓式;作定语...
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野无遗才是什么意思?
意思是:见“野无遗贤”。成语名字:野无遗才成语发音:yěwúyícái成语解释:见“野无遗贤”。成语出处:《魏书·阳尼传》:“举贤良,黜不肖,使野无遗才,朝无素餐。”成语繁体:野無遺才感情色彩:中性成语成语用法:作宾语、定语;指爱惜人才成语结构:偏正式成语产生年代:古代成语...
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穷途之哭是什么意思?
意思是:因车无路可行而悲伤,后指处于困境所发的绝望的哀伤。成语名字:穷途之哭成语发音:qióngtúzhīkū成语解释:因车无路可行而悲伤,后指处于困境所发的绝望的哀伤。成语出处:《晋书阮籍传》:“时率意独驾,不由径路,车迹所穷,辄痛哭而返。”成语繁体:窮途之哭感情色彩:中...
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一如既往是什么意思?
意思是:指态度没有变化;完全像从前一样。一:完全;如:像;既往:从前。成语名字:一如既往成语发音:yīrújìwǎng成语解释:指态度没有变化;完全像从前一样。一:完全;如:像;既往:从前。成语出处:《第二次握手六》:“清末以来,到海外求学的中国人何止千百,在学业上有成就的也大有人在,可...