It's all about circles, really. Longitude is measured in degrees east and west of Greenwich, England. Now, if you've moved the British Isles over by Greenland, that's a significant chunk of water to have moved the Prime Meridian (0° Longitude) by, not to mention the notion that you have to decide if the Empire is still puissant enough in this world to be the ones to make that call.
Anyway, back to circles: if you'll recall Ye Olde Geometry, there are three hundred sixty degrees (360°) to a circle. Longitude goes to +/- 180° East and West of Greenwich, whereas latitude (the parallels) goes in concentric circles, centered on the polar axis -- what this means on your Great Circle is four quadrants of 90° each, and which quadrisphere you're in is determined by the equator (0° latitude) and the 0°/180° line (Prime Meridian/International Date Line).
What they didn't teach us in ninth grade, but you learn pretty damn quick if you want to learn to sail, is this: if you're dealing with a big enough circle, like a Great Circle, one degree is pretty farking huge, so it needs to be split up into sixty minutes ('), each of which can, if needful, be split into sixty seconds ("). Indeed, one nautical mile is defined as one-sixtieth of one degree of longitude as measured at the equator. NB that nautical miles (nmi) != statue miles (mi), although at 1.1508 statute miles to the nautical mile, they may be considered equivalent for rough calculations.
Anyway, you may want to consider how people in your VicMage.China would navigate and mark their maps, as this is all at its base founded on Babylonian principles (360° being one of their holiest numbers, as you can divide a ridiculous number of ways without getting remainders), which your Chinese cartographers may or may not give a fig about.
But really, all I meant to say was that the IDL, she is at 180°0'0" Longitude, not 0'180" (which you should hopefully realise Makes No Sense after all my blather).
Oh, and ° is the HTML-fu for 'a degree symbol,' while I'm being hopelessly pedantic. Then again, you tend to pay as much attention to detail as I do, so you're hopefully not offended by my droning on...
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It's all about circles, really. Longitude is measured in degrees east and west of Greenwich, England. Now, if you've moved the British Isles over by Greenland, that's a significant chunk of water to have moved the Prime Meridian (0° Longitude) by, not to mention the notion that you have to decide if the Empire is still puissant enough in this world to be the ones to make that call.
Anyway, back to circles: if you'll recall Ye Olde Geometry, there are three hundred sixty degrees (360°) to a circle. Longitude goes to +/- 180° East and West of Greenwich, whereas latitude (the parallels) goes in concentric circles, centered on the polar axis -- what this means on your Great Circle is four quadrants of 90° each, and which quadrisphere you're in is determined by the equator (0° latitude) and the 0°/180° line (Prime Meridian/International Date Line).
What they didn't teach us in ninth grade, but you learn pretty damn quick if you want to learn to sail, is this: if you're dealing with a big enough circle, like a Great Circle, one degree is pretty farking huge, so it needs to be split up into sixty minutes ('), each of which can, if needful, be split into sixty seconds ("). Indeed, one nautical mile is defined as one-sixtieth of one degree of longitude as measured at the equator. NB that nautical miles (nmi) != statue miles (mi), although at 1.1508 statute miles to the nautical mile, they may be considered equivalent for rough calculations.
Anyway, you may want to consider how people in your VicMage.China would navigate and mark their maps, as this is all at its base founded on Babylonian principles (360° being one of their holiest numbers, as you can divide a ridiculous number of ways without getting remainders), which your Chinese cartographers may or may not give a fig about.
But really, all I meant to say was that the IDL, she is at 180°0'0" Longitude, not 0'180" (which you should hopefully realise Makes No Sense after all my blather).
Oh, and ° is the HTML-fu for 'a degree symbol,' while I'm being hopelessly pedantic. Then again, you tend to pay as much attention to detail as I do, so you're hopefully not offended by my droning on...
-- Lorrie