M'kay. So, your native Chinese sailors don't give a rat's ass about England -- how much the map is or isn't skewed because England's been towed about like some wayward barge is none of your concern, go you...
But you should come up with how these people are navigating all this mess. Latitude is pretty easy to figure at sea, but longitude has traditionally been a bitch-on-wheels -- in this world.
However, where you're one up on medieval tech is this: you're working in a Mage-based campaign, and as such you have a ready and elegant solution available: all you need is a timepiece with a Time 1 rote in it. As Time 1 IIRC, gives you 'hello, I am an ultraprecise clock,' you can work longitude exactly the same way it was eventually worked out in Renaissance Europe: precision timepieces. Throw in Correspondence 1 (I think?) and you've got GPS decades before its time... although of course it'll express in the mage's own paradigm and expression of units, which means you needn't worry a bit about what cadhla is doing, as your Asian ships' locator doowockies will have been programmed by Imperial mages and will therefore output units of the Empire, and the stupid hairy round-eye barbarians will just have to live with that.
Brlgl. I keep skewing my placement on the time axis -- back here on Tellus Primus, by the Victorian era, the whole precise timepiece idea has long since been dealt with (no quartz, but the clockwork is very good): it was more of a bugbear when the explorers were all afoot. Where your alternate planet is on navigational and cartographical tech, of course, I leave to you, but the bottom line is: latitude can be worked out by anyone with an ephemeris and observational patience and tools (what're you using for sextants?). Longitude is a whole other and more complicated thing, and deserves special mention.
Re: Well, lessee.
But you should come up with how these people are navigating all this mess. Latitude is pretty easy to figure at sea, but longitude has traditionally been a bitch-on-wheels -- in this world.
However, where you're one up on medieval tech is this: you're working in a Mage-based campaign, and as such you have a ready and elegant solution available: all you need is a timepiece with a Time 1 rote in it. As Time 1 IIRC, gives you 'hello, I am an ultraprecise clock,' you can work longitude exactly the same way it was eventually worked out in Renaissance Europe: precision timepieces. Throw in Correspondence 1 (I think?) and you've got GPS decades before its time... although of course it'll express in the mage's own paradigm and expression of units, which means you needn't worry a bit about what
Brlgl. I keep skewing my placement on the time axis -- back here on Tellus Primus, by the Victorian era, the whole precise timepiece idea has long since been dealt with (no quartz, but the clockwork is very good): it was more of a bugbear when the explorers were all afoot. Where your alternate planet is on navigational and cartographical tech, of course, I leave to you, but the bottom line is: latitude can be worked out by anyone with an ephemeris and observational patience and tools (what're you using for sextants?). Longitude is a whole other and more complicated thing, and deserves special mention.
-- Lorrie