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Thread: Converting between map projections?

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  1. #1
    Administrator waldronate's Avatar
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    There are many programs out there that can reproject an image. If you're using FT3, I recommend the following workflow (which is quite similar to Ralf Schemmann's old Jhendor tutorial at http://www.jhendor.de/tutorials/cc2-ft.pdf ):

    1) Use FT3 ( http://profantasy.com/to produce a polar aspect map grid at the resolution that you desire (e.g. Lambert Azimuthal Equal Area projection output to a 4kx4k PNG file Click image for larger version. 

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    2) Use this projection template as an overlay layer in Photoshop and paint your height map in the background. The extremely lazy among use might just rough it in and use something like the process described in http://www.cartographersguild.com/ma...und-lands.html to finalize things.
    3) Use ReprojectImage ( http://www.ridgenet.net/~jslayton/ReprojectImage.zip ) to reproject the world data to the equirectangular projection that FT expects as its binary input.
    4) Use Wilbur ( software ) to flip the image vertically and to convert the reprojected image into a .mdr file.
    5) Use FT3 and create a new world (File>>New) using the binary mdr file saved in Wilbur.

    If you just want to use a picture in FT3 but not height data, you can use the image overlays feature of FT3 to load the output of ReprojectImage directly.

  2. #2
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    Quote Originally Posted by waldronate View Post
    There are many programs out there that can reproject an image. If you're using FT3, I recommend the following workflow (which is quite similar to Ralf Schemmann's old Jhendor tutorial at http://www.jhendor.de/tutorials/cc2-ft.pdf ):
    Awesome, thanks for the reply!

    I will give this a go. I found g.projector last night from NASA, which is really good but it assumes you're starting with a rectangular mercator-type map; there doesn't seem to be any way of starting from a different projection, and I would rather start with an orthographic view and build from there, so your mini-tutorial looks to be just the ticket!

    Thanks again,
    Brian.

  3. #3

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    I'm trying to follow this process in an attempt to move the equator of a map that I'm working on (it was shifted about 45 degrees north), but ReprojectImage isn't available anymore. Does someone have a copy that they could send to me, or a working link?

  4. #4
    Administrator waldronate's Avatar
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    Quote Originally Posted by Mogg01 View Post
    I'm trying to follow this process in an attempt to move the equator of a map that I'm working on (it was shifted about 45 degrees north), but ReprojectImage isn't available anymore. Does someone have a copy that they could send to me, or a working link?
    Try http://www.fracterra.com/ReprojectImage.zip to get ReprojectImage. My ISP killed the ridgenet.net domain without any particular warning and I eventually moved everything to a new host. Everything that was at http://www.ridgenet.net/~jslayton is now at http://www.fracterra.com for your convenience. I don't have any way to path all of the posted paths here on the guild.

  5. #5

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    Awesome, thanks for the super quick responses to a dead thread! ReprojectImage worked like a charm, and my project is back on track! I'll probably mess around with GDAL and MMPS at some point here to see what I can do with them, but I'm already trying to learn 4 new tools for this project, and was hoping to keep the beginning simple. I (obviously) made this account just to beg for ReprojectImage, but given how helpful people seem, I'm thinking I'll hang around and start trying to contribute.

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