You mean like this ?
I added "your" map lowered to be partly covered by water, so you can Play with it.
This is a quick raw convert; due to GG's way of handling such things, you'll need some more "heightmap postprocessing" (hint, hint) and some precise parametrizing to get rid of the "minecraft" appearance.
Edit: lest I Forget: if running the maps, you should see only black space around you, just move upwards.
And set the Player Start marker anew before you run it again
Lives of great men all remind us we may make our lives sublime
