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in reply to Re: Perl and Solving Trig/Converting GPS to x,y Cords
in thread Perl and Solving Trig/Converting GPS to x,y Cords

The Earth is round, but very big.

Between +70 and -70 degrees and distances under about 20 kilometers, bog standard 2D trig will produce results with errors less than 0.2%.

Between +-50 degs, it is less that 0.1%

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
  • Comment on Re^2: Perl and Solving Trig/Converting GPS to x,y Cords

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Re^3: Perl and Solving Trig/Converting GPS to x,y Cords
by roboticus (Chancellor) on Jan 09, 2013 at 13:43 UTC

    BrowserUk:

    That may be true for all the practical cases for the OP, but it's not generally true. A trivial example being several of the polar maps. In those cases, the equator would give terrible results, and the center pole would give similarly good results.

    For anyone interested, some really interesting stuff is at http://www.progonos.com/furuti/MapProj/Normal/TOC/cartTOC.html, especially the "Mathematics of Cartography" section.

    ...roboticus

    When your only tool is a hammer, all problems look like your thumb.

[reply]
      it's not generally true. A trivial example being several of the polar maps.

      How many people are plotting GPS locations inside the artic/antartic circles?

      Especially given that ionospheric signal path distortion renders GPS essentially unusable in those regions.

      With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

        BrowserUk:

        There are plenty of people who would be interested in mapping at the poles: Penguin and Polar Bear researchers, Multi-mega-conglomocorp oil exploration teams, eskimos, extreme sunbathers, etc.

        I was unaware of the GPS difficulties, and the OP didn't really restrict the regions of interest...

        ...roboticus

        When your only tool is a hammer, all problems look like your thumb.

[reply]

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