It is certain, however, that Barker never thought about whether the map was a mercator or some other projection, though fans later would debate the issue.
Thus, the two maps span roughly 5,500 x 4,500 miles in total. Jakálla Map from Empire of the Petal Throneīarker said that each hex of the EPT map was 100 tsan (roughly 133.3 kilometers or 83 miles).
I am not aware of a key to the Bey Sü map, though some description is here and pages 6-7 of Theatre of the Mind’s later Adventures on Tékumel Part Two/Volume One: Coming of Age on Tékumel also might help situate you. EPT’s rear pages include a key to the Jakálla map. In the rulebook (Section 1200 on page 65 of the original TSR EPT) there is a partial description of several of the places marked on the big map. In addition, the EPT box cover was a stylized map of the capital of Tsolyánu, Bey Sü. The original Empire of the Petal Throne (EPT) included two beautiful one-sided color maps each measuring 34″ x 22″ as well as a 28″ x 22″ map of the city of Jakálla. Here’s a deeper dive, but please note that, as usual, a lack of time has led to sloppiness and my not being adequately thorough. The monster response to my last post showing a few Tékumel maps that I had gotten framed has prompted me to think about the history of Tékumel maps a little more systematically. Stylized map of Bey Sü on box cover of TSR edition of Empire of the Petal Throne