How do you add a continental shelf?
In FT3, how do you add a continental shelf?
I realize that you can simply check the "Continental Shelf" box when creating a random map, but I am adding continents manually. I've tried to create them by hand but they just don't look as realistic as the ones created by the program.
I realize that you can simply check the "Continental Shelf" box when creating a random map, but I am adding continents manually. I've tried to create them by hand but they just don't look as realistic as the ones created by the program.
Comments
If you want to try to put in hard-edged features manually you'll be limited by the world editing resolution and as well as by the ringing inherent in the cubic interpolation scheme that FT uses. The resolution part you may be able to deal with. The ringing is much harder to overcome because it will cause overshoots above and below the sharp-edged area. For example, if we start with a flat world and a moderately low seafloor (Tools>>Global Set>>Land Roughness Edit with value 0 and Tools>>Global Set>>Land Offset Edit with value -1000), draw a selection to represent our main outline area, and do Tools>>Global Set>>Land Offset Edit with a value of 2000, we will get an outline that's got a serious ridge around the edge (see attached).
You can reduce the obvious edge somewhat by using a lower step. Starting with the same -1000 baseline above, then running the selection to -200 instead gives less of a jump. If shading is turned off below water level then the jump shouldn't be terribly visible.
One possible workflow to inserting a continent:
Draw your area that will be the outline of the continental shelf.
Use Tools>>Global Set>>Land Roughness with a value of 0 to eliminate the fractal function.
Use Tools>>Global Set>>Land Offset Edit with a value of -200 to get the shelf outline.
Use Select>>Modify>>Contract with at least 3 to pull back the selection from the edge of the continental shelf.
Use Tools>>Actions>>Create Mound From Selection with Min 200 and Max 500 to fill in the basic outline of the continent from 0 to 500.
If you'd like, you can draw another selection where you want mountains and use the mound tool from 0 to 1000 to make a basic mountain-type lump.
I was hoping to still make use of the fractal continental shelf routines though. I have a continent that I've created (raised up the ocean floor with a large feather value in order to create a gradual rise) and was hoping there was a way to get the routines to work their magic on this new continent. Sounds like you're saying there's no way to do that though.
I think what I'll try next is to expand the selection for the new continent and then subtract the original selection, thereby creating a band around the landmass where I want the shelf to be and then trying to smooth that area into resembling a continental shelf. I don't suppose you have any magic tricks for doing something like that do you?
Edit: On the other hand (after spending an hour on that plan), I find that I'm learning to like the look of no shelf.
That's a selection of altitudes between -1000 and -4000 (limited to just around the island), feathered 5, and altitude set to -2500.
http://www.ridgenet.net/~jslayton/CGTutorial/ shows how the prescale tools will keep a continental shelf around the continent as it's worked up from the deep. However, the prescale channel can be a bit fiddly as its units aren't anything resembling real-world units (and the absolute magnitude needed for the tool will vary slightly from world to world).