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Thread: Help for world elevation map

  1. #1
      SeaAngel is offline
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    Help Help for world elevation map

    Hello people! :-) I'm new to this forum and would like a little help...

    I can't say I'm a cartography fan so I don't have any experience, but I would like to create a globe out of something like this: http://www.gma.org/surfing/images/gores.gif
    The aim is to show the relief (relief? elevation? altitude? I'm not sure what is the correct term) of the land and the sea of our planet (I planned to paste extra (and thin) pieces of paper to create greater elevations-I like crafting stuff like that so I hope I won't get bored )
    The problem is, I can't find anywhere a reliable world map that shows the relief. The closest thing I've come till now is this Free Relief Layers for Google Maps (which I found through this forum :-)) but I later found out that the map projection Google Maps is using is a variant of the Mercator, and G.Projector does not support it, so I can't convert it accurately to Sinusoidal.

    Anyway, the points I would like help with are:
    1. Does anyone have or know where I can find a world map that shows the relief?? It doesn't have to be crazy accurate, and it would suffice if the elevation change is every 1000 m (mainly I want the continents to have the correct shape). Also, my project will become SO MUCH easier if instead of colors, the map showed the elevation changes as contour lines. Otherwise I'll have to trace the colored shapes in a drawing program and that would take much more time :-/
    2. Is the Sinusoidal projection really the best for such a project? Or should I try something different?
    3. Would you recommend some other program apart from G.Projector for this project?

    Thanks for your time Also, any other advice you have to give me is more than welcome!
    Last edited by SeaAngel; 09-01-2014 at 04:06 PM.

  2. #2
      Redrobes is offline
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    I had a look around and didnt find anything but there was a nice site discussing the gores projection and lots of maps to make earth there but no elevation. The kind dev (Mitchell Charity) who runs that domain did a nice thing and posted the perl script to make it tho. So I got out a mercator style elevation map which is everywhere and pushed it though the gores projection and it made a nice version for you. I have issues uploading images so I am hosting it. Its public domain in any case since the original came from Nasa.

    http://www.viewing.ltd.uk/Temp/CG/Go...ationGores.png

    All you need to do now is make multiple copies of it and use a threshold for how bright you want each of them to determine the height and then cut all the bits out - good luck with that bit. Might be easier to 3D print it ! Post a pic of your globe when done. We have had a couple done like this before now if you search around.

    Edit - Site reference:
    http://www.vendian.org/mncharity/dir3/planet_globes/
    Last edited by Redrobes; 09-01-2014 at 04:55 PM.

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      Falconius is offline
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    NASA has a greyscale height map of the entire world: Topography | NASA

    Edit: Also it appears to be in equirectangular which would be perfect for G.Projector (makes sense).

  4. #4
      SeaAngel is offline
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    Quote Originally Posted by Redrobes View Post
    I had a look around and didnt find anything but there was a nice site discussing the gores projection and lots of maps to make earth there but no elevation. The kind dev (Mitchell Charity) who runs that domain did a nice thing and posted the perl script to make it tho. So I got out a mercator style elevation map which is everywhere and pushed it though the gores projection and it made a nice version for you. I have issues uploading images so I am hosting it. Its public domain in any case since the original came from Nasa.

    http://www.viewing.ltd.uk/Temp/CG/Go...ationGores.png

    All you need to do now is make multiple copies of it and use a threshold for how bright you want each of them to determine the height and then cut all the bits out - good luck with that bit. Might be easier to 3D print it ! Post a pic of your globe when done. We have had a couple done like this before now if you search around.

    Edit - Site reference:
    http://www.vendian.org/mncharity/dir3/planet_globes/
    Wow! Well, first of all, thanks for the quick reply and all the effort you put to it!! :O You're super nice!

    However, is there any chance you could remake this with 12 gores in stead of 16...? You see, it doesn't represent the elevation in the oceans - I can use other maps for that and combine the data (I have found maps that show the ocen depth :-) ) but G.Projector can't convert anything to or from 16 gores, while 12 is the best choice for the rest of the things I want this globe for...
    If you can't/don't want to do it I completly understand. Thanks for all the effort you've put into it anyway! :-)

    Yeah, I will!

  5. #5
      SeaAngel is offline
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    Quote Originally Posted by Falconius View Post
    NASA has a greyscale height map of the entire world: Topography | NASA

    Edit: Also it appears to be in equirectangular which would be perfect for G.Projector (makes sense).
    Wow, that's quite good! Thanks!!!
    That site also has all kinds of maps! This is super helpfull!
    Last edited by SeaAngel; 09-01-2014 at 05:29 PM.

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      Redrobes is offline
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    ok - hang on...

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      Redrobes is offline
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    If you click on the original link its a 12 tang gore now. You will also notice that its a lot smaller image. If you replace the filename in your browser URL from GlobalElevationGores.png to GlobalElevationGoresLarge.png then you will get the large version which is 12800 wide. By not posting a direct link to it then it might stop the google image spider from indexing it and then prevent my server getting a hammering.

  8. #8
      SeaAngel is offline
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    Quote Originally Posted by Redrobes View Post
    If you click on the original link its a 12 tang gore now. You will also notice that its a lot smaller image. If you replace the filename in your browser URL from GlobalElevationGores.png to GlobalElevationGoresLarge.png then you will get the large version which is 12800 wide. By not posting a direct link to it then it might stop the google image spider from indexing it and then prevent my server getting a hammering.
    Thanks! I think this will work perfectly! (wow, it IS huge )
    You've been very helpful! :-)

  9. #9
    SJS
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    I may be misunderstanding your project here... but if the goal is to create a 3D globe with elevations to scale then the end result will be a completely smooth surface. The diameter of the earth is 12,742 km. The elevation of Mt. Everest above sea level is 8.848 km. This represents a deviation of 0.07%. If the entire globe were 3 ft. in diameter then Mt. Everest would be represented as an increase in height from the smooth surface of the globe of 1/40th of an inch.

    Obviously this is assuming you're doing things to scale, which maybe wasn't your intention after all?

  10. #10
      SeaAngel is offline
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    Quote Originally Posted by SJS View Post
    I may be misunderstanding your project here... but if the goal is to create a 3D globe with elevations to scale then the end result will be a completely smooth surface. The diameter of the earth is 12,742 km. The elevation of Mt. Everest above sea level is 8.848 km. This represents a deviation of 0.07%. If the entire globe were 3 ft. in diameter then Mt. Everest would be represented as an increase in height from the smooth surface of the globe of 1/40th of an inch.

    Obviously this is assuming you're doing things to scale, which maybe wasn't your intention after all?
    Well, you're not wrong! Doing everything to scale would be ideal, but since I don't really want to make a giant globe (and I still want to get the relief), I'll have to make some compromises
    I plan to use the thinnest tracing or layout paper I can find to minimize the error...

    Thanks for pointing it out, anyway! :-) If you have any other feedback on the matter, I'd love to hear it!

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