THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. XXI. — On the Use of the Stereographic Projection 

 for Geographical Maps and Sailing Charts; by S. L. 

 Penfield. 



Introduction. — Maps are generally made by first plotting a 

 system of parallels and meridians, which are then used as 

 guide-lines for locating places, and tracing the outlines of 

 countries, courses of rivers, etc. Numerous methods of plot- 

 ting parallels and meridians have been employed, some based 

 upon exact mathematical principles of projection, others upon 

 geometrical methods of development, while others are wholly 

 arbitrary schemes and have no mathematical justification, 

 hence, as might be expected, the results of map drawing are 

 quite various, and often far from satisfactory. It is of course 

 impossible to represent the curved, bulging surface of a sphere 

 upon a plane without distortion of some kind, and this may 

 become very pronounced if the extent of country covered by 

 the map is large, but still there is no just reason for the marked 

 variations and discrepancies which may be observed on maps 

 in general use at the present time. 



It is not the object of the present communication to enter 

 into a detailed discussion of the general subject of map pro- 

 jection. On the other hand, an endeavor will be made to set 

 forth certain advantages which would result from using a well 

 known method of projection, known as the Stereographic. 

 Attention will also be called to certain misconceptions which 

 seem to exist concerning this most admirable method of pro- 

 jection. 



Doubtless all will agree that maps should fulfil three 

 important requirements : First, the shapes of land and water 



Am. Jour. Sci.— Fourth Series, Vol. XIII, No. 76 —April, 1902. 

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