

Show HN: the Mercator projection like you've never seen it before - mrgriscom
http://mrgris.com/projects/merc-extreme/

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JoshTriplett
Very nice demonstration of the degree of distortion of the Mercator
projection! Most Mercator projections cut off the poles to avoid showing that
distortion, but here, the "pole" sits in the middle of New York City. (Or
other selectable locations.)

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Fuzzwah
I really enjoy explaining this to people (especially Americans when I'm
talking about how comparable my home country, Australia, is in terms of land
mass to mainland USA).

Showing them Bucky Fuller's dymaxion map is always fun.

[http://en.wikipedia.org/wiki/Dymaxion_map](http://en.wikipedia.org/wiki/Dymaxion_map)

[http://www.genekeyes.com/FULLER/Internet-
specimens/dymaxion....](http://www.genekeyes.com/FULLER/Internet-
specimens/dymaxion.jpg)

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ToastyMallows
> Performance on Windows seems generally terrible for reasons I can't be
> bothered to figure out. Sorry.

:( It looks really cool, I'll have to check it out at home.

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nmeofthestate
Works well on IE and FF on Windows, but doesn't work at all on the recommended
browser - Chrome.

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PeterWhittaker
Crashed FF (29.0.1) on Windows (7, SPs unknown): I run with cookies disabled,
cliked on "temporarily allow" in Cookie Monster (1.2), FF died. Restarted,
page took forever to load, slow script warnings, eventually closed tab.

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bshimmin
Is this supposed to be useful in some way? Or just clever? I don't really get
it.

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ljak
I think that it's supposed to demonstrate how inaccurate the Mercator
projection (the one that's used on Google Maps) is at conveying relative size
of continents. For example, Greenland looks enormous whereas it's actually
quite small, while Africa looks much smaller than it is in reality.

Google uses this projection because it's best at preserving angles and shapes.

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bitJericho
What on Earth am I seeing here?

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ljak
> The map you see is the Mercator projection.

> But unlike a standard Mercator projection, you can substitute any point on
> earth as the "pole". (The initial view shows Boston as the pole point)

> Furthermore, this map cuts of much, much closer to the poles than normal,
> allowing you to see many more orders of magnitude of distortion.

> Because this yields a map several times taller than it is wide, it is shown
> sideways from its usual orientation.

> The Mercator projection is infamous for its distortion at high latitudes.
> This distortion gets exponentially worse as you approach the poles. It is in
> fact impossible to show the poles on a Mercator map — they are infinitely
> far away.

> Any Mercator map you've ever seen must cut off the top and bottom edges at
> some arbitrary point. The map stops short hundreds, if not thousands of
> miles away from the poles.

> But I've often wondered what lies beyond those cut-offs... to make a map
> that didn't cut off but simply kept going. As the distortion progresses
> towards infinity, you would eventually reach the scale of cities, houses,
> insects, atoms...

> But of course that'd all be on a featureless expanse of ice. No map service
> even publishes image tiles for such extreme latitudes.

> To make things actually interesting, we must artifically shift the pole of
> the project to a more interesting place. Imagine the earth encased by a
> rigid cage of latitude and longitude lines. We rotate the earth while
> leaving the cage fixed until a new point of interest has taken the place of
> the North Pole.

> This is called an oblique Mercator, and is normally used to shift an area of
> interest onto the equator of the map to avoid distortion. But whereas others
> avoid distortion, we embrace it.

> Note how strange the oblique Mercator looks even without the increased
> cutoffs. The standard Mercator is so ingrained in the public consciousness
> that we perceive it as 'normal'. But once you shift the pole its ubiquitous
> distortion is laid bare.

> Lastly, increasing the cutoffs produces a map much taller than it is wide.
> So it is presented sideways here for easier viewing. (set the pole to the
> North Pole like usual to see this most clearly)

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bitJericho
That was the explanation I couldn't find. Thanks!

