Needed - a modified map of the Earth

[ffutures]

I've looked at the various options for changing the position of the Earth's axis - see previous posts - and decided that I'm going to go with a relatively small change, moving the North Pole about 15 degrees south along the 180 degree meridian, a little west and north of the Bering strait between Alaska and Siberia. This means that London is now at 35 degrees north, not 50 degrees, so hopefully enjoys a mediterranean climate (about the same as Algiers). The North Polar ice cap is probably going to end up close to or touching Siberia and Alaska, but they're used to cold weather there anyway, while the South Pole moves closer to the tip of Africa, and hopefully nothing too drastic happens to the rest of the world. It's still going to be a more or less recognizable map, just a bit distorted.

Niamey in Niger is now on the equator, I think the northern tip of Australia is too, Ecuador is now very slightly south of it, and so forth. You can visualise this to some extent as a sine wave plotted on a normal map of the Earth, with the peaks 15 degrees North of the current equator at the Greenwich Meridian, 15 degrees south at 180 degrees.

The snag is that what I will need is a map of the earth plotted with the new equator as a straight line, and the land masses shifted accordingly. I can probably fake this to some extent by distorting a normal map, but all map projections lie to some extent about the position and size of land masses near the poles, and changing their position without changing the relative sizes will make this worse. I'm not enough of a geographer to get this right. If anyone has software or the skills to do this properly, or can think of a better way to do it, I'd love to hear from you.

I'm not too sure what to do about the degree of axial tilt. 20 degrees or so seems to work well for having seasons and forming nice big ice caps, but would anyone stupid enough to do this in the first place think of that?

Comments

[keristor.livejournal.com]

I was going to ask about the axial tilt. Too small and you get less severe seasons, but on the other hand the north and south are permanently cold (at the current latitude of Scotland, for instance, it would be permanantly like March and not very habitable) and the tropics are wider. Too large and the Arctic and Antarctic Circles move towards the equator, giving warmer summers (more area direct sunlight but colder winters. 20-25 degrees seems a good compromise.

(This is something a lot of SF, and especially visual media SF, gets wrong, with "desert planets" and "forest planets" and the like. You can't have a planet which only has one sort of terrain except in very unusual conditions, like being in a close orbit round a cool star where the solar orbit time is on the same order as the rotation of the planet and with high axial tilt, and in that situation any concept of 'day' and 'night' would be definitely strange. It's dubious if such a planet would be very colonisable. But I digress...)

As for the map, it sounds as though you want a Mercator or similar projection with your altered poles and equator. What you need, therefore, is a 'map' being a full spherical list of coordinates, rotate those (simple trig, just tedious), and then re-project (again, simple trig). The big problem is getting that map in the first place (note that you need the solid ground, having removed the icecaps, then you replace those afterwards).

If someone has such coordinate map, I would be /very/ interested in getting such a list. The alternative, as you say, is to try to reverse engineer them from a standard projection but you'll lose details round the poles.

(Hmm, the BBC must have such a map, for the rotating Earth graphic which they have sometimes morphed into a tumbling cube etc. Possibly not much detail, though.)

Note that the Arctic cap will have become largely open sea on the Atlantic side, and possibly down to Japan on the other side.

[pbristow.livejournal.com]

"The alternative, as you say, is to try to reverse engineer them from a standard projection but you'll lose details round the poles."

I tend to think of the poles as not really *having* details. Unless you count the penguins... =;o}

[keristor.livejournal.com]

Exactly, because they are covered with ice most of the time no one is bothered that (like Greenland on most maps) they are just a white blob. But with the shift in axis the existing poles will be significantly down and Antarcica at least will be partially ice-free. Which then raises the question about wher the actual land boundary is in that area.

[pbristow.livejournal.com]

Indeed. And Antarctica is already a hotly(ironic?)-contested continent.

All we need now is for some Krynoid (http://www.google.co.uk/search?q=krynoid&hl=en&biw=1680&bih=890&prmd=ivns&tbm=isch&tbo=u&source=univ&sa=X&ei=bHVlTunzGpOp8AOWnZiJCg&sqi=2&ved=0CDcQsAQ) or other to throw the cat amongst the lemmings...

=:o}