FT3: Constraining land mass by latitude

Howdy, folk. Apologies if this is the wrong category; I'm totes the clueless newb.

I've read the essentials documentation for FT3, and can't seem to immediately locate a more in-depth manual, so I can't really RTFM on this one. I'm trying to create a world which, as the Hitch-Hiker's Guide to the Galaxy says, "is by improbable circumstance almost entirely tropical islands." Specifically, I'd like to constrain about 90% of the land mass to the area between 30° N and 30° S latitude. Is there a relatively simple way to do this? Is there a relatively complex way to do this?

I thought about just using the raise / lower terrain tool and selecting everything outside the tropics to lower, but... eh. Wanted to see if there was a capability to just generate the world that way, first.

Thanks for your time and attention.

Charlie
Newb in Clownshoes

Comments

  • LoopysueLoopysue ProFantasy 🖼️ 40 images Cartographer
    Oh no, we don't go around telling people to RTFM! (Well, not usually anyway!)

    However, since you mention it, there is a large and comprehensive section all about FT3 in the Tome of Ultimate Mapping, if you would like there to be more information. I am also assuming that you have found the built-in Help?

    There are global raise and lower tools available in the menus, so you could refine that a bit by selecting everything outside the tropics and using one of them?

    There are probably much more refined ways of doing this, but I will leave that to the real experts to describe ;)
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    edited August 2019
    There isn't a way to generate land in only certain latitude bands, sorry. The best bet in this case would be to select the areas that you don't want, feather the selection, and then use Tools>>Global Set>>Land Offset Edit (and/or Tools>>Global Set>>Land Roughness Edit) to push everything down deep. Setting the roughness to about 0.25 will reduce the altitude in that area to a quarter of their previous height, which will make the subsequent offset by a negative value easier.
  • Thanks for the feedback, folk.
  • ... and now I'm encountering another bit of oddity I'd appreciate suggestions for. I was planning to select the tropical / equatorial band and then invert the selection so as to have the mid- and high-latitude areas selected, which would then be feathered, et cetera. But when I tried to select the entire band, the selection snapped to a tiny area on either side of the map's wrap-around, instead of the whole area.

    Help?
  • LoopysueLoopysue ProFantasy 🖼️ 40 images Cartographer
    edited August 2019
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    The most likely cause of this problem is the selection wrapping around the seam at the back of the world (-180 to +180). Use Map>>Set Projection and set Longitude to 0 before doing your selection. to make it easier to do that. Also, it's sometimes easier to use the freehand selection tool to block out rectangular areas because it will work better across the sometimes hard-to-reach map areas than the rectangular selection tool will.

    If that doesn't work, you can use something like paint to create a bitmap that has the area you want to keep in white and the parts that you want to discard in black. The simplest way to do this is to select something in FT3 and use Select>>Save Selection to save the raw bitmap. Then edit the bitmap in something like paint and save it. Finally, use Select>>Load Selection to load that bitmap as the selection and work from there.
  • That worked out perfectly, thanks JSlayton.
  • Late to the party, but if i was doing this I'd just move the poles around till I had the position I wanted. Lazy I guess.
  • 3 months later
  • edited November 2019
    Posted By: Autumn GettyLate to the party, but if i was doing this I'd just move the poles around till I had the position I wanted. Lazy I guess.
    So how does one move the poles around? There's a "North Pole Position Settings" under "World Settings" -> "Secondary", but it doesn't seem to do anything...
  • LoopysueLoopysue ProFantasy 🖼️ 40 images Cartographer
    edited November 2019
    Those controls work with any synthetic world generated by FT3, but unfortunately they do not work on one you have sculpted yourself from a blank base, or on imported data.

    Is yours such a world?
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    The North Pole position setting specifies where to move the North Pole position of the fractal function, not the editing values. Moving editing data is on the wish list for a future version, I hear.
  • Posted By: LoopysueThose controls work with any synthetic world generated by FT3, but unfortunately they do not work on one you have sculpted yourself from a blank base, or on imported data.

    Is yours such a world?
    Yes, it is imported data. That would explain why it hasn't been working.
    Posted By: jslaytonThe North Pole position setting specifies where to move the North Pole position of the fractal function, not the editing values. Moving editing data is on the wish list for a future version, I hear.
    Good to hear, if true!
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