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Old 01-03-2021, 00:59   #1
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Different projection for world mapping

https://earthsky.org/earth/astrophys...sign-world-map

Quote from the article:

You know the old problem of how to portray the round globe of Earth on a flat map? Now a trio of map experts has worked together to solve this problem. Their new map is 2-sided and round.
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Old 02-03-2021, 18:47   #2
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Re: Different projection for world mapping

NOAA (USA) is getting ready to discontinue printed maps, so new projection isn't likely to change things much for us unless Garmin puts it on their screens.
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Old 02-03-2021, 18:58   #3
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Re: Different projection for world mapping

When you zoom in, though, a transverse Mercator projection is still going to be preferable in most latitudes. This is only useful as a whole-earth thing. But it's cool.
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Old 02-03-2021, 22:42   #4
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Re: Different projection for world mapping

I put it here as a general issue of interest to people interested in charting/navigation, not as something that will be implemented in the near future.
As to printed maps mentioned above, it does not matter. All our electronic charts are based on Mercator projection. So if the community will accept the new projection (I do not think it will...) it will be implemented also on our MFD's.
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Old 03-03-2021, 00:20   #5
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Re: Different projection for world mapping

Doe that mean that around the equator you'll have to keep looking at the back of your chartplotter to get the full picture?
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Old 03-03-2021, 01:21   #6
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Re: Different projection for world mapping

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Originally Posted by StuM View Post
Doe that mean that around the equator you'll have to keep looking at the back of your chartplotter to get the full picture?
Well, I am not sure...
As it is a circular projection on flat surface I do not think that looking at the back will be helpful.
But - if we discard the flat screens of current MFD's and install globes in the cockpit....
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Old 03-03-2021, 01:43   #7
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Re: Different projection for world mapping

Sailing across the equator will really be like falling off the edge of the world.
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Old 03-03-2021, 05:52   #8
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Re: Different projection for world mapping

Donwload and print your own: https://vanderbei.princeton.edu/Appe...tMapEarth.docx


Animation:
https://vanderbei.princeton.edu/tmp/Earth_gif.mp4
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Old 03-03-2021, 18:06   #9
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Re: Different projection for world mapping

Wow! - the earth really is flat.
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Old 03-03-2021, 18:44   #10
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Re: Different projection for world mapping

Hmm... that's an interesting definition of "solve". If they're going to complain about how things appear to far apart on other maps, I'm curious how far this makes the UK appear from Argentina.

Since some might find it interesting, here's how the distortion works. Just bear in mind that they're stopping at the equator to avoid worst of it.

Azimuthal equidistant projection with Tissot's indicatrix
Kurubu, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
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Old 03-03-2021, 19:25   #11
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Re: Different projection for world mapping

Quote:
I'm curious how far this makes the UK appear from Argentina.
Depends on what line you follow over the edge to get to it.

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Originally Posted by requiem View Post
Since some might find it interesting, here's how the distortion works. Just bear in mind that they're stopping at the equator to avoid worst of it.
They're not "stopping" at the equator, thery're flipping to the other side so that the distortion decrease again back to zero as you approach the centre. Maximum distortion actually occurs at the equator.


And of course, you don't need to use the equator as the edge, you can use whatever great circle best suits your specific situation.
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Old 03-03-2021, 20:33   #12
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Re: Different projection for world mapping

It's not exactly new either ...
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Old 03-03-2021, 21:22   #13
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Re: Different projection for world mapping

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Originally Posted by StuM View Post
They're not "stopping" at the equator, thery're flipping to the other side so that the distortion decrease again back to zero as you approach the centre. Maximum distortion actually occurs at the equator.

And of course, you don't need to use the equator as the edge, you can use whatever great circle best suits your specific situation.
An interesting view; my mental picture was flipped around to have them stopping there and "restarting" from the south pole.

Your other comment makes me think that if you could easily change the centre point, and thus the great circle split, you would have a convenient means of working out great circle courses and distances. Then again, this implies software rather than paper, in which case why not simply do the maths?

This might actually be a convenient visualisation for planning longer passages, e.g. in OpenCPN, as the ranges to far destinations would remain consistent to the eye.
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Old 03-03-2021, 22:09   #14
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Re: Different projection for world mapping

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Originally Posted by Kelkara View Post
It's not exactly new either ...
Wow, 1672.


Thanks for that, I'd never come across that map before. Very interesting!
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Old 04-03-2021, 00:48   #15
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Re: Different projection for world mapping

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Originally Posted by requiem View Post
An interesting view; my mental picture was flipped around to have them stopping there and "restarting" from the south pole.

Your other comment makes me think that if you could easily change the centre point, and thus the great circle split, you would have a convenient means of working out great circle courses and distances. Then again, this implies software rather than paper, in which case why not simply do the maths?

This might actually be a convenient visualisation for planning longer passages, e.g. in OpenCPN, as the ranges to far destinations would remain consistent to the eye.
It probably will be more mathematically efficient to choose different center points for each voyage.
But, on the other hand, we all hold sort if mental picture of the world in our minds, based on long time of using maps/charts. It will be difficult to get used to a different projection each time.
I see it frequently during sailing. Some people sail with North up chart on the MFD and some like the Head up. And you cannot persuade anyone to switch to the other option.
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