I wrote to Frank Mentzer just now and asked him a map-related question.
Me: "Hi Frank, we (the Atlas of Mystara community) have a question for you." (see attached image)
Frank's response: "Oceans not shown were neither implied or forbidden."
Me: "Thanks! A diplomatic and sphinxian answer!
"It sounds like you're saying that both the Equirectangular (big ocean "not implied") and Mollweide Oval (big ocean "not forbidden") could both be reasonable interpolations. And that your designer's intent was thus ambiguous in this matter."
Frank: "Overall, the entire line puts you in control, dictating as little as possible. You want the Mystara elephant, fine, but it's not required."
Me: "Thanks a million. I'll share this with the Mystara friends. Best wishes!"
After further wrangling between me and Thorf, I wrote to Frank again and he sent a clarification:
Q: Were you and Froideval holding the ubiquitous Mercator projection in mind when you cropped the oval-shaped Time-Life map into a squarish rectangle? A Mercator would be super stretched in the north and south. Or did you simply view that squarish map to be the extent of the world, and that's that. With no thought of projection?
Frank: In truth, space was limited (2 pg interior cover, with key) and it had to be black & white (costs). If I'd've insisted on more ocean, the continents would have been smaller -- the places where all the action occurs. No-brainer graphically. (and btw, I did not imply a smaller ocean. I did not imply a bigger one. And there was no 'team', just Francois sticking his nose in briefly. He could get away with it because we were both Gary's buds.)
Asking me to recall what I considered briefly 35 years ago seems a bit extreme.
Then I posted the "Squashed Equirectangular Urt" map [see attached image], and Frank "liked" it.
Q: Me and Thorf were wondering if you happen to remember the name of the TSR artist (or even just a vague memory of them) who rendered the Master Set map. ?
Frank: Prolly Diesel, maybe Roslof.