Elendel Basin Map:
Longitudinal lines (from left to right):
Iron, Lerasium, Iron, Steel, Tin
Latitudinal lines (from top to bottom):
Atium, Malatium, Gold, Electrum, Chromiun, Nicrosil
Also note how the Elendel Basin is (appropriately) in the northern hemisphere of Scadrial - you can tell because you can see on this map that the meridians converge as they move to the top of the map.
Edit: The Line of Lerasium runs right through Elendel. I propose that the Canton of Cartography is using the lerasium glyph to denote Scadrial's Prime Meridian.
(Edit 2: Because, y'know, it's bookended by Iron on each side. One would be East Iron, the other would be West Iron.)