Philosphere projections

Text and pictures © 2005-2024 Guillaume Dargaud
Last updated on 2018/10/17

"A friend of mine once sent me a postcard with a picture of the entire planet Earth taken from space. On the back it said: 'Wish you were here'."    — Stephen Wright (1955-), american humorist.

What are philospheres ?

When you create a 180x360° full spherical panorama from a set of fisheye images, there's no way you can print the image properly, the distortion is too extreme (it's the usual 'can't print a map of the entire earth' problem). There are web applets (in Java or Flash) that can move your viewpoint around the image but you can't see the whole thing at once. This 'Philosphere' is a trick: it projects the spherical image onto a rhombicuboctahedron (cough, cough) which is taken as an approximation of a sphere. It is simpler to project it onto a cube but the result isn't as nice and funky.

This polyhedron is printed on two separate sheets of paper (part 1 and part 2) and then assembled by hand with scissors and tape (better than glue). It makes a great project for kids on a rainy afternoon when you want them off the computer... Just cut according to the dotted lines leaving some flaps of paper so you can tape the pieces together. The first try is usually not very pretty, but it gets very nice once you figure out the exact cuts and the best way to fold. After you make a first try with a small A4 print, I suggest you make a large print on quality A3 matte paper and assemble that.

How are philospheres created ? You start by making a full 180x360° spherical panorama with appropriate software (PTgui or other panorama tools), which produces a very distorted image with a 2:1 ratio. You then feed it either to the [Utilities][Create PhiloSPhere] tool of PTgui or to the Flexify Photoshop plugin. It gets you two projected images which must be printed at the same resolution. Here are some sets of such images from the first winterover in Concordia for you to enjoy:

Concordia

Left: Philosphere taken below the ConcordiAstro platform. Part 1 & 2.

Right: Philosphere showing Michel cutting wood with a chainsaw right below Concordia, next to the garage, where the wind chill is the fiercest because of the Venturi effect. The radiator of the summer camp power plant lays on the left before the food and garbage containers. Part 1 & 2.

Left: Philosphere showing Michel in the tent used for multiple purpose: as garage for the large Caterpillar and the few snowmachines useless in winter (hidden behind), as woodworking shed and as weather balloon inflation shed. The helium bottles are out of view behind the Cat as well but we inflate in the small space between the doors and the Caterpillar. Part 1 & 2.

Right: Michel working on creating a snowmachine parking structure, where electric plugs can be reached easily to keep the engines warm in summer. This time, if people forget to unplug when running off with a snowmachine, they either won't manage to bring down the structure like the much lighter one at the summer camp, or won't survive to tell about it. Part 1 & 2.

Left: Philosphere showing Jean-Louis picking items in the 'dry' food storage room (the wine is at the very end). There are two additional storage rooms on the same floor: the 4°C room where perishables are stored and the future freezer room, not yet built that's why we simply keep frozen products outside the station in simple containers. Part 1 & 2.

Right: Philosphere taken from the roof of the tunnel linking the first floors of both buildings. Michel is right on the stairs below after having helped me climb on the slippery tunnel and Emanuele is on the plaza, just coming back from storing his snow samples in the container on the left. Notice all the stickers still on the windows, like the average construction site, except that with the cold it now impossible to remove them. Part 1 & 2.