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Mercator Puzzle

gmaps-samples.googlecode.com

21–30 of 96 posts

Re: Mercator Puzzle

#21
Does anyone know why Google insists on Mercator projection? I guess that it makes the implementation bit simpler, but on the other hand you'd imagine that if anyone then Google would have the resources to use some more reasonable projection for greater good.

Re: Mercator Puzzle

#22
answers in the sauce :

var answers = { australia: new google.maps.LatLngBounds( new google.maps.LatLng(-45.379453600000005, 110.69313639999996), new google.maps.LatLng(-8.571888000000001, 155.16969360000007)), southAfrica: new google.maps.LatLngBounds( new google.maps.LatLng(-36.73497648232876, 13.33984375), new google.maps.LatLng(-21.010097985940735, 35.87890625)), greenland: new google.maps.LatLngBounds( new google.maps.LatLng(57.9905285, -75.1942745), new google.maps.LatLng(83.97751860000001, -9.709575500000028)), finland: new google.maps.LatLngBounds( new google.maps.LatLng(59.21319690000001, 19.53808950000007), new google.maps.LatLng(70.7889305, 31.90050659999997)), mongolia: new google.maps.LatLngBounds( new google.maps.LatLng(40.74287280000001, 86.85821429999999), new google.maps.LatLng(52.641200000000005, 121.12602760000004)), thailand: new google.maps.LatLngBounds( new google.maps.LatLng(3.9541530000000003, 95.39209260000007), new google.maps.LatLng(21.477918000000003, 106.6929963)), peru: new google.maps.LatLngBounds( new google.maps.LatLng(-19.255824000000004, -82.93600620000001), new google.maps.LatLng(1.5, -67.99965480000003)), brazil: new google.maps.LatLngBounds( new google.maps.LatLng(-35.42974050000001, -74.69401470000003), new google.maps.LatLng(6.5, -33.06445550000001)), iceland: new google.maps.LatLngBounds( new google.maps.LatLng(62.758218600000006, -25.764343499999995), new google.maps.LatLng(67.1959161, -11.481647000000066)), drcongo: new google.maps.LatLngBounds( new google.maps.LatLng(-15.448980381203414, 9.3359375), new google.maps.LatLng(7.485096269212087, 36.015625)), ukraine: new google.maps.LatLngBounds( new google.maps.LatLng(43.456458529383056, 20.234375), new google.maps.LatLng(53.29973879045674, 42.34375)), madagascar: new google.maps.LatLngBounds( new google.maps.LatLng(-26.898128422978452, 39.5703125), new google.maps.LatLng(-10.366188047247464, 55.3515625)), saudiArabia: new google.maps.LatLngBounds( new google.maps.LatLng(14.77959730788355, 33.41796875), new google.maps.LatLng(33.68098354643421, 57.28515625)), mexico: new google.maps.LatLngBounds( new google.maps.LatLng(11.700047540913861, -119.90234375), new google.maps.LatLng(34.264084202839264, -83.65234374999994)), mauritania: new google.maps.LatLngBounds( new google.maps.LatLng(12.387690937704622, -18.7890625), new google.maps.LatLng(29.336753501211746, -2.3046875)) };

Re: Mercator Puzzle

#23
post #21

Does anyone know why Google insists on Mercator projection? I guess that it makes the implementation bit simpler, but on the other hand you'd imagine that if anyone then Google would have the resources to use some more reasonable projection for greater good.

I have been waiting for MANY years for them to do something about this. At least after the XKCD strip came out. http://xkcd.com/977/

Re: Mercator Puzzle

#24
post #21

Does anyone know why Google insists on Mercator projection? I guess that it makes the implementation bit simpler, but on the other hand you'd imagine that if anyone then Google would have the resources to use some more reasonable projection for greater good.

I think this is an externally visible link: http://productforums.google.com/forum/#!topic/maps/A2ygEJ5eG... . It's the answer I received when I filed an internal bug on this.

"Hi John - Thanks for the feedback. Maps uses Mercator because it preserves angles. The first launch of Maps actually did not use Mercator, and streets in high latitude places like Stockholm did not meet at right angles on the map the way they do in reality. While this distorts a 'zoomed-out view' of the map, it allows close-ups (street level) to appear more like reality. The majority of our users are looking down at the street level for businesses, directions, etc... so we're sticking with this projection for now."

Re: Mercator Puzzle

#25
post #21

Does anyone know why Google insists on Mercator projection? I guess that it makes the implementation bit simpler, but on the other hand you'd imagine that if anyone then Google would have the resources to use some more reasonable projection for greater good.

I think this is an externally visible link: http://productforums.google.com/forum/#!topic/maps/A2ygEJ5eG... . It's the answer I received when I filed an internal bug on this. "Hi John - Thanks for the feedback. Maps uses Mercator because it preserves angles. The first launch of Maps actually did not use Mercator, and streets in high latitude places like Stockholm did not meet at right angles on the map the way they d…

Yes, there are two properties that are important for Google Maps:

1. Mercator is conformal, which means angles are preserved. So if you zoom into any small part of the map, it will look right. Equal-area maps distort angles.

2. North is always in the same direction—up. Together with the conformal property, it means that all directions are preserved: North, South, and everything else.

The primary use case for Google Maps is not to show the whole world at once, rather it is targeted at street-level mapping. Hence, Mercator is an ideal choice.

Re: Mercator Puzzle

#26
It's crazy how much Mercator distorts the globe. I was playing around with various map projections via WebGL shaders [1] and the size problems really stand out when the map is recentered. With modern digital maps, we should really stop using old projections that were designed to work on limited paper maps.

[1] http://sxp.me/maps/ (Select equirectangular as the projection and drag the crosshairs to recenter.)

Re: Mercator Puzzle

#27
post #21

Does anyone know why Google insists on Mercator projection? I guess that it makes the implementation bit simpler, but on the other hand you'd imagine that if anyone then Google would have the resources to use some more reasonable projection for greater good.

I think it's got to do with preserving north south east and west angles. Also, the distortion is only noticeable when you're zoomed out. When zoomed in most things are in relative proportion to each other.

Re: Mercator Puzzle

#28
I have been wishing for a long time to have an outline feature in Google maps (or any map tool for that matter). I always want to compare the size of things (partly because of the distortion of the projection), say is the city of SF larger or smaller than NYC? I was stoked when Google added city boundaries, so that means they know them. Now there just needs to be a way to select a city, state/province/department/whatever, or country and drag it somewhere.

Re: Mercator Puzzle

#30
post #21

Does anyone know why Google insists on Mercator projection? I guess that it makes the implementation bit simpler, but on the other hand you'd imagine that if anyone then Google would have the resources to use some more reasonable projection for greater good.

I think this is an externally visible link: http://productforums.google.com/forum/#!topic/maps/A2ygEJ5eG... . It's the answer I received when I filed an internal bug on this. "Hi John - Thanks for the feedback. Maps uses Mercator because it preserves angles. The first launch of Maps actually did not use Mercator, and streets in high latitude places like Stockholm did not meet at right angles on the map the way they d…

Not sure if this makes sense, but couldn't they have different projections for different zoom levels?
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