Happy birthday Mercator!— Oops

[daan]

Today is Gerhard Mercator’s 500th birthday. Mark Monmonier kindly notified me of this German commemorative:

German Mercator stamp

Mercator stamp.jpg (205.03 KiB) Viewed 763 times

He sent it with question, “What’s wrong with this stamp?”

So. Have at it. What’s wrong with the stamp?

— daan

[ndzinn]

Well, perhaps it's because the stamp suggests that the Mercator projection can be constructed perspectively. It can't ... but that's inside cartography. OK for a stamp, I think. -Noel

[daan]

Bingo! The portrayed projection isn’t a Mercator. It’s a cylindrical perspective. Indeed, if the image I have has correct aspect ratio, then the projection is a “central cylindric” with a vertical stretch of 1.09, though there is some asymmetry north versus south. The southern stretch is more like 1.11.

— daan