FT3: bringing most land below 2,000' elevation/altitude

Hello and thank you for entertaining my question. I can imagine that I am missing something obvious in my searches.

On my map, I stared with earthlike altitude extremes in the settings. Most of my altitude map is green, but unlike Earth these lowlands are from 0 to 4k'. The least highland can still get up to 9k', and is not uncommon. The link below shows a sort of baseline for what I am aiming for. My world and its climates would make a lot more sense to me if elevation were distributed something more like it is on Earth, where 2k' is a highland and 6k' is already unusual apart from high peaks.

http://my.ilstu.edu/~jrcarter/LDEO/Geo201maps.htm


http://forum.profantasy.com/comments.php?DiscussionID=6416&page=1#Item_3

I see this method with which I could go piece by piece around the world and give it a range? Are there other good ways to get earthlike heights distribution onto my current map and altitude scale? If I start over, should I just start with a low extreme so most of the land ends up like on the Earth histogram linked above, and then paint the actual mountains everywhere?

Comments

  • When I made a few flatish worlds for my Traveller site, I went to the Map menu at the top of FT3. Selected World Settings. Then on the Primary tab, typed in a new Highest peak, and Lowest Depth.

    I just tried it again, and it kept those height/depth settings through several worlds. Then I exited the software.

    Hope that helps.
  • VirVir Surveyor
    Thanks, Jim. Yes, I put in there 30k each since that's how it is on Earth. Doing so leaves very little land in the low altitudes, and so unlike Earth. I could definitely restart with low extremes and then add the rarer, higher ground to taste. But if I can keep using my current map with only as much bother or less, I'd rather.
  • I actually just go through and lower the land in some areas as suggested in the tutorial. I find that way I can keep the land near the coasts higher, and create lower inland areas. It usually takes me about 2-3 hours but it really allows you to sculpt where mountains should be, and get the proper distribution of land. There are a few quicker things you can do, if you prefer. For instance, you can select a height range, and only incise that range. So for instance you can choose between 2000 and 6000 feet, say, and incise them, or just pick an elevation for them. I've had some good results from, say, selecting 2000 -4000 feet, and then setting the height of all of them to 2000 ft. Then select 4000 to 6000 feet, and set them all at 3000 feet. Keep working your way up. At the end, of course, you have to smooth it all out at a fairly low value, then fill basins and such.

    Anyways, those are a few methods I've experimented with. I'm assuming that you know how to do all this stuff. If not, just ask.
  • I meant, type in 2000 replacing the 30000 feet. I should have been clearer.
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    FT uses a simple split exponential function to create the illusion of continental shelves (it raises all points below the continental shelf value to the 0.5 power and all points above the continental shelf value to the 2.0 power). The default -1000' value for the continental shelf results in most of the "flat" area near the apparent continental slope is under water. One way to get more of the world above sea level is to set the continental shelf value in FT to a value much closer to 0, perhaps even to 0 itself.

    The attached graph shows what FT does to a world's computed altitudes with continental shelf values turned off (green) and on (orange). Note that the original distribution of values out of the fractal function is not as uniform as shown on the chart, so this chart does not represent exactly what you get. It would be nice if FT has a histogram window to show the final computed distribution of altitudes on a world.
  • Interesting. Now, for bigger continental shelves on future Traveler planets on my site.
  • VirVir Surveyor
    This is great info! I'll see what I can work out over the weekend and learn what's next to learn. Thanks, all.
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    edited March 2019
    As a bit of technical trivia, you can affect the land and sea exponents for new worlds by editing a .srf file with something like Notepad. There is a field called "Misc" that has five values on the line. The first two values are the land exponent (greater than one) and sea exponent (less than one). Increasing the land exponent will give you flatter areas in the low parts of the world (I don't recommend going much above about 3), and decreasing the sea exponent (getting closer to 0) will give you flatter ocean floors and a steeper continental slope. If you increase the land exponent, you probably want to put your continental shelf altitude very close to zero. Note that the values in the srf file only affect new worlds based on that value.

    If you have a world that you're invested some time in editing and you would like to adjust the exponent, the following might work for adjusting an existing world:
    0) make a backup of your current .ftw file.
    1) In FT, use Map>>World Settings to bring up the World Settings property sheet. Click the Selection tab to show the selection page. Click the … button and select a temporary directory to work with (it you installed to the default location and aren't running as Administrator, you'll be unable to write to the protected installation directory). Click the Save button, give the file a name, and click OK. You should now have a file with that name and a .srf extension in your specified directory.
    2) Exit FT.
    3) Navigate to the specified directory and edit the .srf file with something like Notepad. Locate the line starting with "Misc" and change the first two numbers to 3.0 and 0.4 (leave the rest of the numbers on the line alone). Save the file.
    4) Start FT again, select your item on the Selection tab of the World Settings property page, click Load to load the settings, and then click Apply. Your world should now have new information about the shape of the landforms. You'll need to reset any continental shelf value that you might have changed.
    5) Save your file.

    The attached image shows the result of the technique above (before and after). The big star is obvious editing data that was preserved across the operation. Note, however, that editing across continental shelves may change appearance. Also note that the coastline changed shape a bit because coastal areas were flooded. If you don't want the coastlines to change shape, you will need to set your continental shelf altitude to zero, which causes the loss of continental shelves worldwide.
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    Changing the exponent and shelf changes the curves:
  • LoopysueLoopysue ProFantasy 🖼️ 40 images Cartographer
    Wow! :D

    Would this adjustment continue to work for all new worlds as well?

    (Sorry Vir - I was silently reading along, but I just needed to know the answer to this question)
  • If I find a similar string of world seeds gives me worlds I don't want right then, I take out the zeros from the seed and click Apply. Sometimes I get what I want.

    Since I use FT3 for my Traveller site, I use it for water, temperate, and waterless worlds. I keep a spreadsheet of values from the World Settings tab in case I want to try more with the basic world.
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    edited March 2019
    Posted By: LoopysueWould this adjustment continue to work for all new worlds as well?
    The adjustment is a property of the srf file. Any world sequence generated from that srf file (which includes all of the next world/previous world ones) will retain the exponent settings.
  • LoopysueLoopysue ProFantasy 🖼️ 40 images Cartographer
    Excellent! :D

    I've been looking for an easy way of making the lowlands flatter for aaaaages!
  • I notice in your example that the islands are lost. Is this generally the case, or is it a feature of this map only?
  • jslaytonjslayton Moderator, ProFantasy Mapmaker
    It's a general feature of changing the exponent because making the coastal areas flatter will result in more of those areas being underwater. If you want to preserve exact coastlines, you need to start with continental shelf at 0 altitude or tweak the coastal shelf altitude until you get coastlines very much like your original ones.
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