Re: Question

From: David B. (davidb_at_tronospamchos.freeserve.co.uk)
Date: 07/14/04 

Date: Wed, 14 Jul 2004 23:14:58 +0100

Martyn Harrison wrote in message
<796bf0pq1vjilvfg8je06ruac7bvf0320a@4ax.com>...
>
>> http://www.trochos.plus.com/primesauce/later.htm#84
>
>What I'm getting at is the question of whether Mercator projection was
actually
>a new idea as such, or just an existing idea popularised via that name.

To the best of my recollection, the specific mathematics of the Mercator
projection (actually very slightly wrong as he drew it, but soon fixed)
were his idea. He was after all working only a generation after the very
first documented circumnavigation of the planet. Previous world maps had
been most concerned with representing the shapes of the continents, to
which end they used all sorts of exotic projections but Mercator addressed
the problem of navigation, which had gone way beyond the old portolan
techniques.

>I reckon the conical projection does have some real advantages in
estimating
>distance within a northern hemisphere ocean voyage such as an Atlantic
>crossing. In that sense, I'm wondering whether Mercator was something
nobody
>had thought of (I find this rather unlikely, although obviously it may be
the
>way of it), or whether it was adopted for some reason (and what reasons
those
>might be.)
>
>The obvious thing is it reflects an entire globe moderately well and is
>extremely easy to map lat and long into a rectangular space.

It's not just lat and long; the brilliant thing about the Mercator
projection is that it gives a good representation of directions- take a
bearing on the map and, despite the fact that you're sailing on a globe,
steering in that direction will get you pretty close to where the map says
you're headed. To do that, distances have to be sacrificed- which is why it
was a dumb idea to use the Mercator projection as a standard representation
of the world in household atlases.

David B.

Relevant Pages

  • Re: Question
    ... >>What I'm getting at is the question of whether Mercator projection was ... >To the best of my recollection, the specific mathematics of the Mercator ... which had gone way beyond the old portolan ... was achieved by mapping the coastline relative to a known heading, ...
    (sci.archaeology)
  • Re: Credibility Revisited...
    ... peculiarities some folks feel should be considered in Mercator ... projection, but there's some evidence that you might. ...
    (rec.scuba)
  • Re: Question
    ... and Tom obviously don't know that's that. ... "David B" skrev i meddelandet ... I thought you knew the publications of Mercator, ... > example, was the map ...
    (sci.archaeology)
  • Re: 1507 text ref of Inventio Fortunata
    ... > where this caption appears on the Ruysch map) by the 1470s. ... Fortunata, and if true, logically there was more to cnoyens ... Fine, Mercator, in his 1569 world map, and Hadji Ahmed, among ...
    (sci.archaeology)
  • Re: Question
    ... Inger E Johansson wrote in message ... ... >>Please just tell me which Mercator map you're talking about. ... >>I've got PhotoShop LE, and will take my chances with trying to ...
    (sci.archaeology)