It's almost certainly him just converting the maps to high-rez so he can sell them on his website.
This
It's almost certainly him just converting the maps to high-rez so he can sell them on his website.
I am of two minds. I love Greyhawk BUT my current campaign is set in Greyhawk and if they release new canon, it will probably step all over what I have laid down in my campaign!

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.