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Hai-Etlik
01-31-2012, 04:00 PM
I have a rather old lamp with a plain conical shade that has fallen apart and two thoughts occurred to me: I could make one of those, and if it's a cone, I could use a conical map projection to decorate it.

So I measured it, and started playing with the idea in Geogebra.

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The angles on the right are the standard parallels for an equidistant conic projection. The angles on the left are the parallels where the top and bottom of the shade would be.

Initially I had used the top and bottom of the lamp shade as the standard parallels, but then I realized I could reduce the distortion by moving the standard parallels in a bit. Hence the points F and G. I then tweaked them to get the distance between the projection surface and the sphere about equal at the top, bottom, and middle.

So now I just need to decide if I want to use some real world data or a made up world, and make a map out of it using this projection.

junius_gallio
01-31-2012, 04:21 PM
Neat! I have seen commercial lampshades done with an older, "Age of discovery"-style map, but had never thought of doing something like that myself.

Hai-Etlik
01-31-2012, 04:36 PM
Neat! I have seen commercial lampshades done with an older, "Age of discovery"-style map, but had never thought of doing something like that myself.

Yes, though I doubt they would have gone to the trouble of projecting the map onto a surface the same shape as the lamp shade. I readily admit that it's stupendously geeky and obsessive.

Coyotemax
01-31-2012, 04:44 PM
Maybe so, but I think it's worth doing.

photos!!!

junius_gallio
01-31-2012, 04:58 PM
Yes, though I doubt they would have gone to the trouble of projecting the map onto a surface the same shape as the lamp shade. I readily admit that it's stupendously geeky and obsessive.

Oh, no--these weren't projected--when you saw the seam, it was quite obvious that they had cut the shades from material where the map was simply printed as a flat map on a flat sheet. These "lampshade projections" are just too cool!

I second Coyotemax--pics when finished!

Hai-Etlik
01-31-2012, 04:59 PM
Crap, I just realized I screwed up. The slant length of the projected cone would be the length of the arc, not the segment. This is going to be a bit more complex.

dangerdog15
01-31-2012, 08:40 PM
This sounds fun.

Hai-Etlik
01-31-2012, 09:14 PM
This sounds fun.

Not so fun after a few hours of trying to solve it.

Hai-Etlik
01-31-2012, 09:48 PM
OK, I'm pretty sure I've got it this time.

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I ended up cheating a bit. I constructed H' such that arc HH' would be the correct length sₒ given any particular H and I, and then adjusted I until H was at the right distance from the y axis.

Hai-Etlik
02-01-2012, 04:50 AM
I've decided to do a map of Earth in the style of my Baakoi map. I'm currently putting together some data from free sources in QGIS, then I'll export to SVG and load into Inkscape for styling.

ravells
02-01-2012, 04:59 AM
Yes, though I doubt they would have gone to the trouble of projecting the map onto a surface the same shape as the lamp shade. I readily admit that it's stupendously geeky and obsessive.

Which means we all have a lot in common :)

Lukc
02-01-2012, 05:04 AM
Go Hai-Etik, go! :) I support your project!

Redrobes
02-01-2012, 09:06 AM
What are you going to make the shade out of ? Is it a print or a print to vinyl ? Or are you going to cut out a mask and let the light shine through to project the map onto the blank shade ?

anstett
02-01-2012, 10:03 AM
Just a quick thought (besides cool idea) would be to make perforated with a small hole punch.

Have the light shine out to highlight cities on the map. Or even do one of the constellations of your world.

BOB

who has not given up hope of one day putting that fiber optic star field up on the ceiling.

Hai-Etlik
02-01-2012, 10:37 AM
What are you going to make the shade out of ? Is it a print or a print to vinyl ? Or are you going to cut out a mask and let the light shine through to project the map onto the blank shade ?

Well, I plan to get it printed on a large format injet, so it should be a heavyish paper. It'll probably need some sort of reinforcing under it though I haven't decided what yet. The original shade was a sort of fibre reinforced plastic attached to the wire frame with a heavy paper tape. I'll probably need to actually get it and find out how stiff, durable, and permeable to light it is to figure out the details.

I am thinking of using a fabric tape at the top and bottom to attach to the frame and form a border.

Hai-Etlik
02-01-2012, 04:12 PM
Well, I'm seriously stressing my poor computer with this project, but the results are looking quite nice. Here's North America so far.

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Hai-Etlik
02-01-2012, 09:51 PM
Getting even slower, but almost done with designing the map.

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anstett
02-01-2012, 11:14 PM
A new entry for the list: http://xkcd.com/977/

Lamp Shade Projections

Very cool project.

BOB

Hai-Etlik
02-02-2012, 05:19 PM
A few more refinements.

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I did a render at 360 DPI and it took hours.

Lukc
02-02-2012, 05:30 PM
It's luvli! Dangit. What software do you use to get these transformations of territory to different projections? I wants it!

Hai-Etlik
02-02-2012, 05:43 PM
It's luvli! Dangit. What software do you use to get these transformations of territory to different projections? I wants it!

I used Geogebra to work out the standard parallels I needed to fit the shape of the lamp shade, QuantumGIS to prepare and project the data, and a custom program in Ruby to make the graticule (though QGIS could have done that as well)

And obviously I used Inkscape as I always do for the graphics.

ravells
02-02-2012, 06:44 PM
That is beautiful. You should sell those lampshades through a kickstarter project!

Lukc
02-03-2012, 02:58 AM
QuantumGIS. Gotcha. More stuff to learn. :D

Hai-Etlik
02-03-2012, 03:12 AM
QuantumGIS. Gotcha. More stuff to learn. :D

There are a few other desktop other GISes to try playing with: GRASS, uDig, OpenJUMP, gvSIG. GRASS probably isn't what you want, but I've heard uDig and OpenJUMP are fairly approachable. Or if you are made of money, there's ArcGIS; even the absolute bottom of the line license makes Photoshop look inexpensive.

Hai-Etlik
02-05-2012, 03:56 AM
Printing has been problematic. I've tried 6 different print shops. The first two would have done it for a reasonable price, but both of them were having problems with their wide format printers. The next two both wanted in the vicinity of 7 times what the first to would have charged, and the last two didn't have wide format printers at all.

However, I have printed it out in sections on my own printer and have glued them together to get a prototype.

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anstett
02-05-2012, 08:37 AM
Have you tried online photography places like Shutterfly? I know they make poster sized prints, not sure if the paper they use is thin enough to let the light shine through properly though.

BOB

Hai-Etlik
02-05-2012, 10:35 AM
Have you tried online photography places like Shutterfly? I know they make poster sized prints, not sure if the paper they use is thin enough to let the light shine through properly though.

BOB

I have a local photo place that does large prints and they are even more expensive still. Over 100 CAD for the size I need. It's not urgent so I'll just wait for one of the first two.

dangerdog15
02-07-2012, 03:03 PM
This has turned out so well. I used to work at a family owned art store. During our free time, we'd work on projects like this (lamp-shades, hand-made sketchbooks, etc.) and the store would sell them. Can't wait to see the final product.