This is a MapHist list message (when you hit 'reply' you're replying to the whole list) o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o +
for it might be of general interest I give to the list the private response to a message by Robles Macias. Dear Dr. Robles Macias, I have seen the article by Snyder it (J.P. Snyder, Navigation, vol. 2, nº1, March 1949, pp.2 – 5): TERRIBLE! It is uneasy to understand even to me, teacher of Projective Geometry! Horrifying!!!! We have to take in mind that Snyder was a geodesist and a mathematician not a geometer. I use a very simple method which allows in one hour or less to draw any kind of gnomonic meridian projection. If you use autocad or a graphic software the grid is perfect and you may freely use it for any purpose. I use a double Mongian (orthogonal) projection fo the sphere covered with meridian and parallels at the distance I like (5°, 10°, 15 . . .) and than project the sphere and the grid into a chosen oblique plane. From the double intersection I have the exact position of any point of the grid. Meridians and Equator are obviously straight lines while the parallels are ellipses, one parabola, and hyperbolae. As the method of taking projections (not geographical ones but perspective projections) was known also to Piero della Francesca, it is easily believable that in the XVII century scientist might know it and use it. Ancient people was not so stupid to waste their time in complicated and absurd construction as we do today. Come to Venice. ciao vladimiro _______________________________________________ > MapHist: E-mail discussion group on the history of cartography > hosted by the Faculty of Geosciences, University of Utrecht. > The statements and opinions expressed in this message are those of > the author and do not necessarily reflect those of the University of > Utrecht. The University of Utrecht does not take any responsibility for > the views of the author. > List Information: http://www.maphist.nl > > Maphist mailing list > [email protected] > http://mailman.geo.uu.nl/mailman/listinfo/maphist > > <Snyder_1949_GraphicalConstructionGnomonic.pdf> _______________________________________________ MapHist: E-mail discussion group on the history of cartography hosted by the Faculty of Geosciences, University of Utrecht. The statements and opinions expressed in this message are those of the author and do not necessarily reflect those of the University of Utrecht. The University of Utrecht does not take any responsibility for the views of the author. List Information: http://www.maphist.nl Maphist mailing list [email protected] http://mailman.geo.uu.nl/mailman/listinfo/maphist
