. Elements of precise surveying and geodesy. hefeatures near the edges of the map arecrowded together so as to appear un-natural. For instance, in the lower dia-gram of the figure, which shows an ortho-graphic projection of the northernhemisphere on the plane of the equator,it is seen that the distance betweenparallels of latitude near the outer partsof the map is much less than near the central part; in theupper diagram, which is an orthographic projection on theplane of one of the meridians, a similar distortion is alsoobserved. A projection devised by Flamsted to avoid this distortionconsis
. Elements of precise surveying and geodesy. hefeatures near the edges of the map arecrowded together so as to appear un-natural. For instance, in the lower dia-gram of the figure, which shows an ortho-graphic projection of the northernhemisphere on the plane of the equator,it is seen that the distance betweenparallels of latitude near the outer partsof the map is much less than near the central part; in theupper diagram, which is an orthographic projection on theplane of one of the meridians, a similar distortion is alsoobserved. A projection devised by Flamsted to avoid this distortionconsists in dividing the central meridian NS into parts pro-portional to the distance be-tween the parallels, and throughthese points drawing straightlines to represent those paral-lels. Each parallel is thendivided into the same number-^ of equal parts, and the merid-ians are drawn through thesepoints of division. All the trapezoids between two givenparallels thus have the same area, and the distortion is lessthan in the orthographic 190 GEODETIC COORDINATES AND PROJECTIONS. VIII. A projection devised by Bonne is constructed in a similarmanner to that of Flamsted, except that the parallels areconcentric circles. The center of these circles is in themiddle meridian and at a distance of a cotL from the middleparallel whose latitude is L; thus in representing half of thehemisphere the radius of the middle parallel is equal to the TV
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