Comments on: Is there any software that will dynamically re-project a map as you click-and-drag it?

Question: Is there any software that will dynamically re-project a map as you click-and-drag it?

Sleeper — Wed, 26 Sep 2012 07:45:44 -0800

Is there any software that will dynamically re-project a map as you click-and-drag it?

Is there any existing software that will let you click and drag the map and show you a new projection as you change the focus (what falls in the center) of the map? (The map would use wraparound--whatever goes "offscreen" on one side immediately appears on the other side, north-south and east-west). It would be cool to do this with projections other than the Mercator, too.

I'd like to see a map where e.g. Mexico is distorted the way Greenland usually is. Something that could distort the globe dynamically.

A dynamically distorted map would make it easier for students to understand how maps show you the world as if through a fisheye lens. Is there such a thing? If not, what would it take to write a program that could do this?

I was on a long plane ride earlier this year staring at the flight path map and I got to thinking about globe projections and how distorted they are.

The most popular globe projection, the Mercator map, distorts Greenland into a huge landmass comparable to Africa. Everything is distorted. It's like looking through a lens that warps the size and shape of everything, especially around the edges. All map projections do this to some extent.

(I was also going to ask what it would take to photograph a person's head from all sides and project it to a flat surface, to use it as another tool to emphasize how badly flattening distorts a round object, but then I realized that Eric Testroete (the big-head Halloween costume guy) beat me to it.)

By: mcwetboy

mcwetboy — Wed, 26 Sep 2012 07:59:21 -0800

I do not know whether these apps will do what you want specifically, but you might want to check out Flex Projector and NASA's G.Projector.

By: XMLicious

XMLicious — Wed, 26 Sep 2012 08:00:44 -0800

I haven't come across anything that does this dynamically but you'll probably be interested to know about NASA's G.Projector software, which is a free application that will take a standard image file of a cylindrical projection and let you choose from 90 different projections to reformat it as.

By: yurivish

yurivish — Wed, 26 Sep 2012 08:20:10 -0800

The d3 visualization library has some examples that are similar in spirit to what you're looking for:

Animated transitions between map projections, and more in the gallery, if you scroll down to the Maps section.

d3 is a javascript data visualization framework, and the code for those examples is available right on the page. If you're handy with programming that should help you create the map that you'd like to see for yourself.

By: XMLicious

XMLicious — Wed, 26 Sep 2012 14:59:06 -0800

Spelunking around the d3 gallery that yurivish linked to I found exactly what you're asking for.