Well, even though it's only for trade, that Piltover map still tells us a lot. We see Piltover/Zaun (can we please start calling them the Twin Cities?), Bilgewater, the corner of Ionia, and Noxus. We also have directional arrows for Demacia (west along the coast) and Freljord. The Freljord arrow also points west, and since we know it's cold, it probably means that the western coast turns northward somewhere off the edge of the map. We also know from the Demacian lore that Freljord raiders are an issue for them. And we know from the Black Mists that the Shadow Isles are somewhere out beyond Bilgewater.
Pay attention as well to those red icons over many of the cities. Most of them are the red ax of Noxus, which likely indicates Noxus influence or control of the settlement. The fact that they seem added - and in some cases along the southern coast of the middle sea, replacing the Shuriman icon - seems to indicate relatively recent expansions of Noxian influence to these locations. IIRC from one of Taliyah's stories, her return from Ionia to Shurima passed via Freljord. If the Noxians are in control of Shurima's ports along the middle sea, it makes sense that she would need to take the long way around the northern continent to access Shurima from the west.
Those sailing times are also telling. A few minutes of researching historic sailing speeds shows that this narrow sea is comparable to the Mediterranean Sea IRL - maybe a bit larger.
Overall, the geography of Runeterra is looking very similar to our Old World. We have a long east-west sea (Mediterranean). The continent to the south has a lot of desert (North African coast with the Sahara further inland), while the continent to the north is dominated a major empire*, Noxus (compare to Rome or a more united Christendom). We have a major trade hub on the east-west sea that is using its income from trade to push technological innovation (compare to Renaissance Italy). We have a mythical land to the east with ninjas and samurai (western perceptions of Asia). We see several cities that started out under Shuriman influence now under Noxian influence (comparable to the Crusades).
*From what we've seen of the new Demacian lore, I get the impression that Noxus and Demacia are not equals the way they were implied in the old lore. I get the sense that Noxus is a major empire and Demacia is more of a protected enclave that is so far from Noxus, the Noxians haven't bothered to devote the forces necessary to subduing it . I get the sense that Noxus = Roman empire or Catholic Europe while Demacia = Britain, even if it doesn't end up being an island; we know they suffer from Freljord raids, as the English did from the Vikings.
