Commons:Featured picture candidates/Image:Fernão Vaz Dourado 1571-1.jpg

From Wikimedia Commons, the free media repository
Jump to navigation Jump to search

Image:Fernão Vaz Dourado 1571-1.jpg - featured[edit]

Short description

  •  Info A pre-Mercator nautical chart of 1571, from Portuguese cartographer Fernão Vaz Dourado (c. 1520-c.1580), one the best cartographers of his time. It belongs to the so-called plane chart model, where observed latitudes and magnetic directions were plotted directly into the plane, with a constant scale, as if the Earth were plane. The text in the border reads: in this sheet it is drawn all the coast of Africa and Guinea up to S. Tomé Island (Portuguse National Archives of Torre do Tombo, Lisbon). This is the very first time that I bring my present work here... Created, uploaded and nominated by Alvesgaspar 10:38, 6 March 2008 (UTC)[reply]
  •  Support -- Alvesgaspar 10:38, 6 March 2008 (UTC)[reply]
  • Weak  Support I know this is a funny thing to say about such a large image, but a bit higher resolution would make the text a lot easier to read. Otherwise, excellent. Adam Cuerden 12:19, 6 March 2008 (UTC)[reply]
  •  Support--Mbz1 15:50, 6 March 2008 (UTC)[reply]
  •  Comment geocode and an additional category once you determine 'where' it is? -- carol 15:51, 6 March 2008 (UTC)[reply]
    •  Question Geocode? Sorry, I'm not following you - Alvesgaspar 16:03, 6 March 2008 (UTC)[reply]
      • I would like to compare the location this hand drawn map (a compositon of navigation notes and while at sea scrawling?) to a satellite view of the same area from a more recent mapping of it. Eratosthenes determined the circumference of the earth and was accurate to 1% some 1400 years before this. I suspect that this map should be very good compared to a photograph. -- carol 03:15, 7 March 2008 (UTC)[reply]
        • I suspect you'll need to adjust the photo to map from sphere to flat plane - this map covers a substantial chunk of Africa. --WikiWookie 03:51, 7 March 2008 (UTC)[reply]
        • Eratosthenes was only lucky, that is the accepted explanation among geographers... We cannot compare this kind of nautical chart (or any kind of nautical chart, for that matter) with a satelite image because they have different methods of representation. In all charts of this period (until the middle of the 18th century) the latitudes, magnetic courses and distances observed at sea (and also on land) were plotted directly on the chart plane, ignoring the roundness of the Earth. Not because they were ignorant of that fact but due to the constraints imposed by the navigational methods of the time. Only when accurate time could be obtained on board (after Harrison's invention of the maritime chronometer, about 1750) and the spatial distribution of magnetic declination was known with adequate accuracy could the pilots abandon the use of the so-called "plane chart" and fully adopt the Mercator projection (which was presented in 1569, almost two centuries before). The reason? Accurate time was necessary to determine longitude on board and the knowledge of the magnetic declination was necessary to correct compass directions and use "true" geographic directions. Alvesgaspar 09:22, 7 March 2008 (UTC)[reply]
  •  Support Fascinating. --MichaelMaggs 17:26, 6 March 2008 (UTC)[reply]
  •  Support --WikiWookie 03:51, 7 March 2008 (UTC)[reply]
  •  Support as per above --Booksworm 07:17, 7 March 2008 (UTC)[reply]
  •  Support great detail for a photo --Ianare 18:46, 7 March 2008 (UTC)[reply]
  •  Support --Nice, rare and valuable reproduction. Thanks Alves ! Sting 14:06, 8 March 2008 (UTC)[reply]
 8 support, 0 oppose >> featured -- Alvesgaspar 14:41, 19 March 2008 (UTC)[reply]
Retrieved from "https://commons.wikimedia.org/w/index.php?title=Commons:Featured_picture_candidates/Image:Fernão_Vaz_Dourado_1571-1.jpg&oldid=10557468"