I got into a discussion about sea water and coral with Fly77 on discord. [On the wrong channel.
Oups!]
Me: "It also should be noted that coral reefs have clearer water. Light gets deeper.
Real coral is a long way off. We need a noisy terrain mesh with a very bright multicolored surface. Then over this we could add static coral and moving fronds of soft coral, seaweed and anemones as a complex 'grass'. I also mentioned this on the water blog post from years ago."
Openstreetmap marks coral reefs with reasonable accuracy. Down to 20m. Coral reefs are done as dark blue dots on the sea. If we can extract that as we do roads then we have a useful heat map of coral but a extraction of the color alone by color filtering will also get waterfalls some text. Adding a little noise and limiting to under sea depth will work. We would end up with a little stray coral in lake Eyre and a few other named lakes that are below sea level.
"Or you could use sea depth, latitude, the temperature and rain fall map. There are very few places where that would put a reef in the wrong place. Also adjacency to other reefs and islands would help. The problem would be sea grass meadows. I'll look for a map for those. They are the exception. Did I mention that I'm an ecologist."
Cameni said.
this would be probably more viable, all the data are already available
forests use a forest mask, so the trees can only be where the mask asserts it
that's also the reason why some islands do not have trees, the global tree mask data do not cover them
but it's possible to turn off the forest data and use climate-computed coverage, which we used before without the forest mask
I guess it would make sense to use the same approach for corals
I added: "If it works for corals then it will work later for kelp. Sea weeds, some other things. Even some semi random schools of fish. It is not urgent. I'm just trying to work out if I can be useful. {and the UN data base I found has Kelp and sea weeds. }
The key question is are the sea depth on the continental shelves and bigger Islands approximately right?"
I also since found this data base.
https://data.unep-wcmc.org/ This does coral down to ~15 m.
The same site does a dozen other marine ecologies. Sea grasses, mangroves, salt marshes. etc. This map also has the sea bed terrain including mid oceanic ridges and abysses marked as shading. That may be useful.
I am looking at blender tools to see if I can create a coral texture with normal map and emissive. If we can't change the global light level then adding a tiny bit of day time emissive will make the coral look like its in clearer waters. Corals being filter feeders produce clearers seas below them as do sea grasses.
A few coral structures, called bombies at the small scale, and some coral and sea grass models for decorating the reef and the sand flats between the reefs and shore will take a while. I'll see what I can do.
