I'm still ploughing my lonely 200nm furrow out here.

I've been messing around with the GTOPO30 database recently, which lets me
generate maps of fixed-width coastal zones automatically. GTOPO30 contains
elevation data at 30 arcsec intervals for the whole earth, and so has a
resolution of one km or less. This seems ideal, since islands that fall below
the 1km resolution of the data are unlikely to fit the UN's requirement for
"habitable" land from which Exclusive Economic Zones can be extended.
But:
a) GTOPO30 is missing data for a few islands that fall well within its
resolving capacity - San Andres & Providencia in the Caribbean are missing,
for instance.
b) Some EEZ claims are based on tiny islands that are not in the least
habitable in the conventional sense - the UK bases a chunk of its EEZ on
Rockall, for instance.

So after much fiddling, I've been able to generate some nice EEZ maps, but
not entirely automatically - some islands have to be put in by hand.

Attached is my first effort at showing the Everone's Land enclaves within the
Caribbean EEZs. Land is in black, sea in blue, EEZs in cyan.
The Gulf of Mexico contains a large area that is more than 200nm from any
inhabited land, and the central Caribbean contains another, smaller area. But
maps of real-world maritime boundaries generally show the Gulf area
containing two separate smaller areas of high sea, and none at all in the
Caribbean. Why?
What shuts down the Gulf area seems to be a Mexican claim based on various
reefs and cays: Arrecife Alacran, Cayo Nuevo and Cayo Arenas. I've shown
these claims in a darker shade of cyan, since I suspect they might not meet
the letter of the UN definition. There's also a little rim of darker cyan in
the east of the Gulf, arising from the Dry Tortugas. (I do know these have
been inhabited in the past, most prominently by the infamous Dr Mudd, but
that word "Dry" tends to support my contention that they're not habitable in
the strictest sense.)
The Caribbean high seas enclave is closed off in practice by the meeting of
the Columbian and Jamaican EEZs along a treaty line. Presumably the larger
extent of these EEZs is based on more cays and reefs: Columbia claims a raft
of these east of the San Andres and Porvidencia Islands, and Jamaica own the
Pedro and Morant Cays. EEZs constructed around the eastern cays of Columbia
and the southern cays of Jamaica completely close off the "high seas"
triangle, so again I've mapped it in dark cyan.
I'm still trying to track down a copy of "Maritime Boundaries of the World"
to enlighten by speculation, but meanwhile I'm enjoying what amounts to
experimental geography - seeing what the computer generates, and then
matching that to what's going on in the real world.

Grant