projecting

[kmusser]

I have a new favorite comic: http://xkcd.com/977/

Yay for geography in-jokes. I'm generally an Albers Equal Area guy myself.

Surprised he didn't go for a Buckminster Fuller joke in there.

Comments

[craig trader (from livejournal.com)]

He left out my personal favorite: McArthur's Corrective Universal Map:

http://odtmaps.com/detail.asp_Q_product_id_E_McA-23x35

[zammis.livejournal.com]

of course you have to like one NOT on the list. :P

[andrewducker]

Could you illuminate me as to the problematic nature of the Peters Projection?

[kmusser]

Well the thing about it that pisses off geographers isn't the projection itself, but Peter's academic dishonesty. He claimed to invent a new projection that corrected the problems with the Mercator projection and trots out a projection that was invented 100+ years earlier. To add insult to injury it doesn't actually correct the problems with Mercator, if your main beef with Mercator is that it distorts the polar region, replacing it with one that distorts the equatorial region isn't really much of an improvement - you ought to be going for one that tries to spread out the distortion, which most professional cartographers were already doing. There is a lot more about it in the map's wiki article.

[andrewducker]

How does it distort the equatorial region? My understanding was that everything is shown in proportion to the actual land area it takes up. Is that wrong?

[kmusser]

It keeps the areas correct, but distorts directions and shapes - which all equal area projections do. Equal area projections have a standard parallel where the shapes are correct and the distortion will get worse the further away from that you get. The Gall-Peters projection puts that at 45°, which is much farther away from the equator than other equal area projections, as a result the equatorial areas get stretched out, the N-S direction is longer than it should be and E-W is shortened.

[andrewducker]

Aaah, gotcha.

So which projection does equal area with the least distortion?

[kmusser]

If you're doing a world map, probably Hobo–Dyer. If you're only doing one hemisphere you can get even better with Albers.

[andrewducker]

Cheers. I shall remember that next time I'm ordering a map!

[chuck-lw.livejournal.com]

I have shoes with toes in them, and I use a Dvorak layout on my cell phone, but I've never seen this dymaxion map before. Is it going to stick with me now?