Hi!! I have GostTown a 3ds Max plugin that can use OSM to build towns.

But the problem is that the maps looks skew or compressed more you get away the 0:0 coordinate.

Can you explain why?

asked 10 Mar '13, 10:23

Ornix24's gravatar image

Ornix24
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accept rate: 0%


This sounds like it's a projection issue.

Map co-ordinates are usually measured in 'degrees' of latitude (y / vertical) and longitude (x / horizontal). All of OpenStreetMap's data is stored in co-ordinates like this. Have a look at a spherical globe to see how big a degree is.

If you simply draw your map such that each degree is represented by a constant distance - say, 1cm on the map for 1 degree of the world - then the map will end up squished in exactly the way you describe.

A 'projection' determines how much space on your screen/print-out each degree takes up. To avoid this squishing effect, a simple projection - such as the one used on most mapping sites, technically known as 'Spherical Mercator' (or 'Web Mercator') - gives more space for each degree of latitude (y) as you get further away from the equator. (In this projection, each degree of longitude takes up the same space.)

You therefore need to tell Ghost Town to use a different projection. You'll need to ask on the forums for that product how to do that.

(For a more light-hearted look at projections, see this xkcd cartoon.)

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answered 10 Mar '13, 15:57

Richard's gravatar image

Richard ♦
29.2k40259390
accept rate: 19%

edited 10 Mar '13, 15:58

Great !

Thank you For your quick answer (and the terribly funny cartoon) !

I will give it to KilaD, the amazing guy who created this very useful plugin. I hope it can help...

(10 Mar '13, 17:01) Ornix24
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question asked: 10 Mar '13, 10:23

question was seen: 1,668 times

last updated: 10 Mar '13, 18:09

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