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Thread: How do I make a Azimuthal Equidistant Map?

  1. #1
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    Help How do I make a Azimuthal Equidistant Map?

    I've tried twice to make a Azimuthal Equidistant map, once in PS with Filter > Distort > Polar Coordinates and the second with G.Projector. Both times I didn't like the way it was distorting and made everything look stretched. Is there a way to circular background in PS and I can just plot my landmasses there? Or is there another way that I may not know about?

    Any help you guys and gals could provide would be greatly appreciated.

  2. #2

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    Can you provide an example of what you don't like?

    Depending on how your land masses are distributed, orthographic projections of opposite sides of the globe might be appropriate.

    What type of map projection are you starting from? Or are you using a 3D paint program to draw directly on the surface of a sphere?

    Sometimes multiple gnomic projections of relatively small areas are an appropriate starting place. There are programs which can then stitch them together on the surface of a sphere or reproject them into whatever format that you prefer.

    All 2D flat maps of a 3D spherical surface have to stretch or shrink things somewhere. You have to choose a projection that best shows the type of information that you're interested in. https://en.wikipedia.org/wiki/List_of_map_projections shows examples of many projections.
    Selden

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    Quote Originally Posted by selden View Post
    Can you provide an example of what you don't like?

    Depending on how your land masses are distributed, orthographic projections of opposite sides of the globe might be appropriate.

    What type of map projection are you starting from? Or are you using a 3D paint program to draw directly on the surface of a sphere?

    Sometimes multiple gnomic projections of relatively small areas are an appropriate starting place. There are programs which can then stitch them together on the surface of a sphere or reproject them into whatever format that you prefer.

    All 2D flat maps of a 3D spherical surface have to stretch or shrink things somewhere. You have to choose a projection that best shows the type of information that you're interested in. https://en.wikipedia.org/wiki/List_of_map_projections shows examples of many projections.
    I'm trying to come up with a projection like the one below. IMG_3379.JPG

    I drew an equirectangular map and was able to distort it to polar coordinates and got IMG_3380.JPG

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    Guild Expert johnvanvliet's Avatar
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    do to the polar pinch that is rather LARGE it dose not look like you started with a "equirectangular map" map
    there is no real polar stretch in the reprojcted image


    as you get near the poles in a "simple cylindrical" map the east/west distance gets LONGER looking



    now this was done using the gimp reproject to and from polar
    and it is only somewhat accurate

    but good enough for most things

    for a real accurate remap you need to use a GIS program like the open-source QGis
    it uses GDAL to remap geo-referenced images


    there is also MMPS
    http://www.users.globalnet.co.uk/~arcus/mmps/

    this dose a good job for a lot of things


    but you can use gimp to "fix the polar pinch then re-project it

    like this
    Last edited by johnvanvliet; 08-10-2017 at 01:15 PM.
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