Vol. IV, pp. 101-116, pl. 17 March 31, 1892 



THE 



NATIONAL GEOGRAPHIC MAGAZINE 



THE MOTHER MAPS OF THE UNITED STATES. 

 BY HENRY GANNETT. 



(Presented before the Society January 22, 1892.) 



Introduction. 



We read of topographic maps and of geographic maps. Both 

 of these classes of maps represent similar features — the drainage 

 and other bodies of Avater, the relief of the earth's surface, and 

 the artificial features, such as railroads, roads, towns, houses, etc. 

 The distinctions between them are merely those of scale and of 

 area represented. A map on a small scale and covering a large 

 area is commonly known as a geographic map. 



Mother maps are those made from original sources of informa- 

 tion. Commonly they are the maps for the production of which 

 a survey was carried on, while compiled maps are secondary 

 productions, being reduced or changed in certain respects from 

 the mother maps. Topographic maps may be mother maps or 

 compiled maps. Geographic maps are in most cases compiled 

 maps. 



Most of the countries of Europe have been surveyed under a 

 uniform plan or system and mother maps produced therefrom. 

 In these cases the mother map is everywhere of uniform quality 

 and character. In the United States, on the other hand, many 

 partial survej^s have been made under independent authorities 



:5— Nat. Geog. Mag., vol. IV, 1892. (101) 



