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icosahedron
09-24-2009, 05:33 AM
Does anyone have an Earthlike planet that they could drop in here?

Celestia and similar software seems to produce photorealistic planets, and I need a pic of a planet in space, without getting hammered for copyright.

Clouds are good, provided they don't obscure the Area of Interest - the border between the northern ice cap and some greener land.

It would be good if you could include some zooms of the Area of Interest, going as far as possible without obvious pixellation (I don't know if Celestia zooms onto planets).

I want to use it (them) as a base to inset my own map into, using Viewingdale.

I'm not planning to profit from it, but I'd like to display my derivative here and elsewhere.

Thanks.

Gidde
09-24-2009, 08:16 AM
Celestia does zoom in; the amount of zoom is dependent upon how large the resolution is of your map.

I've been itching to play with celestia a bit anyway; I could probably help you out if you can wait a couple weekends. Did you have a planet already in progress? Celestia textures are basically 3 maps -- an equirectangular map (think Ascension's atlas tut and much much darker than is intuitive), a bump map that corresponds, and a cloud layer. So if you have an equirectangular (or any projection I can flexify into it) sketch, I can go from there.

selden
09-24-2009, 08:46 AM
Your software info mentions that you have Fractal Terrains. You can use it to generate a full-planet map. If you export that map's variants as png images, they can be used with Celestia.

Celestia is just a viewing program which has been optimized for astronomical uses. It wraps "Cylindrical Equidistant" (Plate Carré) maps around spheres (in orbit around stars , etc) which you can then examine. It can display maps as large as your computer can handle.

Unfortunately, the VirtualTextures that it uses for extremely high resolution surface maps are somewhat awkward to generate.

A web page which discusses Celestia's use of texture maps is at http://www.lepp.cornell.edu/~seb/celestia/textures.html

icosahedron
09-24-2009, 11:21 AM
Thanks guys.

I don't have a map of a world-in-progress, this is something of a one-off and I didn't want to put anyone to any trouble.

Any old blue and green planet you've already made would do, if it has an ice cap.

I'm just experimenting with a map-nesting technique and I need a globe to nest another map into. I could use a public domain Earth-in-space shot, except Earth's a bit cheesy and I'd have no zoomed in shots.

The zoomed in shots are just to help prevent the globe pixellating as I zoom in to my tiny map area. (if that makes sense).

I have Fractal Terrains in my sig but it's years since I used it, it's an old version and it isn't currently loaded on my computer. When I get around to some serious planet building, I'll see what else is on the market and decide where to go from there. :)

Gidde
09-24-2009, 12:48 PM
Ok then, I'll generate one up with planetgen. It makes some decent globe shots if you don't let it place mountains for you ;)

Ascension
09-24-2009, 08:17 PM
There are some planets in my planet tutorial, have fun with them if you want.

http://www.cartographersguild.com/showthread.php?t=3388

Zeta Kai
09-24-2009, 08:28 PM
Check out this world & see if it's what you're looking for; made by me in Photoshop:

17033

icosahedron
09-25-2009, 02:40 PM
Thanks guys.

Zeta, I've used your icy planet. my WIP is here:

http://www.cartographersguild.com/showthread.php?t=7225

However, detailed though it is, you can see the limitations on the WIP thread. I don't know if Gidde's planet could solve that problem?

If not, maybe this is the best I can get until I start to produce my own planets. (thanks for the tut, Ascension). :)

Gidde
09-25-2009, 03:19 PM
Hmm, a planetgen planet probably wouldn't have a whole lot more detail. I'll look over at the celestia resources page and see if they have a non-copyrighted planet with high res.

selden
09-25-2009, 04:02 PM
Don't forget that If you want a single high resolution image of the entire planet's surface, that implies a gigantic file. For example, 8192x4096 map would have a resolution of only about 5km per pixel at the equator and be about 128MB uncompressed. Improving the resolution by a factor of 2 increases the file size by a factor of 4.

A fractal planet generator will take quite a while to generate a really large planetary map.

selden
09-25-2009, 05:21 PM
FWIW, here are three 8K texures in jpg format (to keep their sizes down). They're the surface texure, bumpmap and specular map.

These 1-2MB maps have serious defects when examined closely due to the lossy JPEG compression. The accompanying planetary image and closeup were generated by Celestia. For them I used the lossless PNG equivalents of the JPEG maps, which were more than 5MB apiece. The original uncompressed PPM images were 96MB each.

The land-and-snow-locked lake in the upper center of the planet image and in the closeup is split across the edges of the surface map at its upper right and left corners..

The maps were created using the fractal planet generator "planet" by Torben Ĉ. Mogensen running under Cygwin on a 1.86 GHz Core2Duo system running Windows XP. Each map took a little over 8 minutes to generate from the seed 0.74321

icosahedron
09-29-2009, 02:26 PM
Cheers Selden,

Here's a pic showing your regional detail set into Zeta's planet, and then a zoom to show my original inset inside that.

The more levels there is, the better it looks.

However, I'm beginning to think that I should go with a simpler planet render, eg from something like Fractal Terrains, as it will be easier to match insets that way.

Thanks guys, with your help my little experiment has been a success and has given me much food for thought. :)

PS. Can someone tell me how to insert the word 'taken' into the thread title? I changed the title on the first post, but it didn't change it in the thread title.
Thanks.