¶ Projective Transformation (2)
← Projective Transformation (1) | Projective Transformation (3) →
Index Entry
How can I get a total surface to give me the best information? In traditional methods of projection such as Mercator, polyconic, or polar-azimuthal, there is only one point, or line, or pair of lines where there is a true reading: that special line along which the conically or cylindrically curved paper is in actual contact with the sphere. From the line of true contact, accuracy diminishes outwardly in projection. The errors increase very rapidly, particularly in the Mercator projection in which the sphere is split open from the great circle of the equator and spread flat so that two points in the middle of Russia are split to the map’s ends and seem to be 25,000 miles apart. “I have found then, that instead of trying to use infinitely severed lines with two polar azimuthal projected hemispheres breaking the whole Earth into two separate circular planes, or the polyconic projection with the northern and southern hemispheres projected as fan-shaped planes with their curved edges tangent to one another at only one point, it is possible to avoid introducing infinity within the projected system.” - RBF, Univ. of Rhode Island, 26 Aug. '66. p. 196.
