[Fractal Terrains 3] Help Converting An Existing Fractal 'Donjon' World Map

Hello all,

I've been trying to follow the instructions here and in this similar thread. I am messing up somewhere, though.

I'm starting from a fractal world map created using Donjon tools. The map was originally created in 2014, and has been in use with my small writing RP, so I do want to keep it as close to the original as possible, but I realize some change may be inevitable. FT3 seems like amazing software and I think it would help add depth to the world map (both literally and metaphorically).

My original map
My best failed attempt

Am I screwing up something obvious, perhaps?

Any help would be greatly appreciated. Thank you.

Comments

  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    It looks like you're running across the problem of signed vs. unsigned in the numeric representation. A small negative number is equal to a large positive number in the 2's complement notation used by most modern computers. For example, a value of -1 has a 16-bit 2's complement representation of 32768, or almost exactly in the center of the 0 to 65535 range of an unsigned 16-bit integer. I am guessing that you are using a 16-bit integer output from Wilbur such as the Muse DTED format rather than the MDR format. MDR stores height values in such a way that they can't be misinterpreted in this way.

    The simplest way to fix the height values would be to check the "signed" box on the Binary data dialog in FT during the import phase. The next simplest way would be to use MDR as the transfer format from Wilbur to FT (you need to remember to flip the image in Wilbur before saving it as MDR because I screwed up the MDR translation at one point).

    There is one other point that you might consider: what are you going to do with the map? If you just want to reproject it, you can import your original color image directly into FT as an image overlay.

    If you can color-reduce the image (an operation called "posterize" in many image editing tools) to a manageable number of levels (say, 16), then you should be able to import the color-reduced image as an image overlay and then use FT's color to altitude conversion tool to associate altitudes with the colors on the map.
  • It took me a lot longer than I care to admit to get it working, but the Image Overlay seems to be the ticket. Thanks for your help!

    However, is there a way I can improve the level of detail it retains? Something in the settings maybe?

    For instance, I have a small group of islands that almost entirely disappears.

    The overlay
    After 'Color to Altitude'
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    The color to altitude conversion results go into your offset editing channel, meaning that your final resolution will be the resolution of your world editing data rather than the resolution of your input. For best results, make sure that your world editing values is at least as large as your world map. In the case of this map, your image was 4000x2000 samples, meaning that your world editing data should be at least 4000. Use Map>>World Settings, select the Editing tab, click Custom, enter 4000 (6000 might be a good choice as well) in the editing field, and click Apply.

    FT uses a cubic interpolation technique, which can result in overshoots and undershoots at sharp steps. You may get cleaner visual results by using the raw height field option (Map>>World Settings, Secondary tab, check the Raw Height Field checkbox) after converting your color image to altitudes. The Raw Height Field option ignores everything except your offset editing channel and uses a linear interpolation operation that avoids overshoots and undershoots.
  • Perfect!

    Sorry for all the newb questions, but thank you again for all of your help. I'm normally the type that doesn't mind spending time experimenting with settings to see what all I can do, but I just couldn't find a solid place to start from.
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