My own Map

I wanted to make my own map, and plot­ting sys­tem. Here’s what I imagined.

Zoomed In - Logarithmic Spiral on Azimuthal Projection

Zoomed Out - Logarithmic Spiral on Azimuthal Projection

Note: This post is a sum­mary of all that I’ve read, and found to be related to this spe­cific idea of mine — I don’t really know what I can do that would be counted as entirely ingenuous.

How the images above were made:

    • plots for the log­a­rith­mic spi­ral plot­ted, were obtained from Wolfram|Alpha, with a=0.5, and b=0.02 ran­domly put into the r=a*e^(b*theta)formula for a log­a­rith­mic spi­ral, so that the arms were rel­a­tively tight.
    • the “zoomed-in” Gno­monic pro­jec­tion of the globe, if from Wikipedia’s arti­cle on the same.
    • the “zoomed-out” one, below, is from this ran­dom … thinige’s site, taken and used with­out per­mis­sion (though, with appar­ent, attribution).

I got the “inspi­ra­tion”, from Escher’s Spi­ral Globe, the image of which, I first saw in The Infi­nite Book.

Escher Spiral Sphere

On a bit of look­ing around, I found out that that thing is called a Lox­o­drome, and it a log­a­rith­mic spi­ral pro­jected onto a sphere. The cool thing, and why I want to use this map sys­tem, is that on a spe­cific plot, I can use just one angle to spec­ify where I am, as the dis­tance from the cen­tre, is only a func­tion of the angle. It obvi­ously reduces the fidelity two pieces of infor­ma­tion pro­vide, as in the case of a lon­gi­tude and lat­i­tude angle, but I can add the piece of infor­ma­tion about which lon­gi­tude I am using as my X-axis, and then cover all locations.

What’s the ben­e­fit? By my cur­sory read­ing about this, the Rhumb line is sim­i­lar to some­thing called a Great Cir­cle Route, (though this might be severely wrong, and just some sort of name con­fu­sion, because the wiki arti­cle about the Rhumb Line specif­i­cally talks about the severe dif­fer­ence between this Rhumb Line, and the Great Cir­cle Route) which is the straight­est point between two points, used by air­craft routes, and looks like a lat­i­tude  curve join­ing the two points. I don’t know how, yet, but some­how I could spec­ify the trans­la­tion of the ori­gin, such that the source and des­ti­na­tion lie on the same arm of the spi­ral, and again two angles would be ade­quate to spec­ify along which course the plane should be navigating.

Under­stand­ing an azimuthal projection:

Stereographic projection of a sphere onto a plane

Rhumb Line Coolness:

Loxodrome -  45Loxodrome - from the top

  • http://devikablogs.wordpress.com/ Devika

    * clue­less *
    iLike the pic­tures, though :P

    Ha ha human­i­ties… ;)