Page:The New International Encyclopædia 1st ed. v. 13.djvu/45

* MAP. Homeric conception of a flat circular earth sur- rounded by the ocean. With the Renaissance, liowever, I'toleiny's work again came into use, and when wood and copper engraving began to be employed for the reproduction of maps cartog- raphy made rapid progress. To satisfy the in- creasing requirements of navigation, the Italians produced a series of nautical charts called loxo- dromes, in which all points were connected with 31 MAP. The earliest attempt to construct a map of an extended territory U|)on a trigonometric and to- pographic survey — that is. upon modern sclentifio principles — was made in 17.3.3 by Cesar Cassini, the director of the astronomical observatory at Paris. Assisted at first by the French Academy of Sciences and afterwards by a private company, he undertook to map the entire area of France. The first sheets appeared in 1744 and the last PTOLEMV'8 MAP (C. 150). each other by straight lines, which represented compass bearings and enabled the navigator to lay out his course to any objective point. With the progress of geographical discoveries in the fif- teenth, sixteenth, and seventeenth centuries, map- making became an established industry in Ger- many and Holland. To this period belong the great cartographers — .Johann Werner, of Nurem- berg, who in 1513 devised the equal area cordi- form projection; Gerhard Kramer, generally were completed in 1793. The work aroused widespread interest among all civilized govern- ments, and so forcibly illustrated the value of accurate maps that the French Government soon imdertook an elaborate survey, an example that has been generally followed in Europe and Amer- ica. Theory of ItlAP Construction. As it is im- possible to make the surface of a sphere conform with a plane, the problem of representing por- OBTOOGRAPHIC PBO.IECTION. known as Mercator, who invented the first de- veloped projection and published a map of the world (1569); Ortelius, the publisher of an atlas, Thratnim Orbis Tcrrarum (1570); and Blaeu (died 138), author of Atlas Xoriis. Ho- mann (died 1724) issued the first school atlas. Alias Scholasticus. !Mercator's projection prac- tically revolutionized the method of map-making, as it solved for the navigator the complex prob- lems involving the relations of courses and dis- tances to latitude and longitude. '00 80 eTEREOGRAPHIC PROJECTION. tions of the earth's surface upon a map can be solved with only approximate accuracy. The solution may be approached by various methods which lead to results more or less valuable for particular purposes. Among these methods are the orthofirnphic and stcreor/raphic projections of Hipparchus, the (/nomic projection of Thales, and the f/lohular or e<juidistnnt projection devised by Niccolisi. These projections, which are based upon the relative positions of the eye and the plane of projection, are best adapted for the