There is a saying, "The map is not the territory". While there are many reasons why this is true, there is one aspect regarding maps of the whole Earth that caught my interest quite a while ago. The Earth is more or less a sphere, how do you project a sphere on a plane? By distorting it, of course. Knowing that maps are distorted projections is one thing, getting a feel for that distortion is another.
If you could animate a map by continously changing the projection point, you could get a better understanding in which ways and to what extent different areas of the map are distorted. A few weeks ago I just realized that the individual frames of such an animation could be generated by xplanet and then an animation can be created by joining together all these frames. Since you don't want to manually generate all the frames you would need a way to automate the whole process. I wrote a short Python script that generates the frames by calling xplanet in a loop and then creates an avi animation using mplayer.
xplanet supports quite a few projections: ancient, azimuthal, hemisphere, lambert, mercator, mollweide, peters, orthographic and rectangular. For each projection I generated three animations: clockwise rotation, latitude change and longitude change.
You can download the script and generate the animations yourself, make sure you have xplanet and mplayer installed. I uploaded all the videos to Google Video. Just search for title:distortion in motion and you will see all of them. Unfortunately it seems that you will have to install a Google video viewer (Windows only) to be able to play them. For the rectangular projection there are no latitude and rotate animations (xplanet cannot generate them).
As a sample, you can download the Azimuthal longitude, Mercator latitude and Mollweide rotate from here.
Some ideas for the future: xplanet 1.2 is out and it has more projection types. I am sure that there are more efficient ways to generate an animation. One thing I was considering is to generate a SMIL script, I just don't know how to convert this script (and a whole bunch of individual frame images) into a compressed animation.
Similar work: Antonin Roussel has a series of similar animations, his focus is on moving around Earth.
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