Worldmaps to view the planet in 3D?

[selden]

Redrobes,

Celestia automatically subdivides single imagemaps. I don't know what its limit is for individual images, although it is a 32bit application, so it can't work for one as large as 2 GB. However, it essentially exposes that subdivision mechanism in its VirtualTextures. At the highest resolution level, it's limited to the size of texture that your graphics card can handle. Modern high-end cards can handle individual textures as large as 4K on a side, although older ones are limited to 1K on a side.

Celestia VTs can handle as many as 13 levels of subdivision, for a maximum VirtualTexture size of 4Megapixels x 2Megapixels if 512x512 pixel tiles are used. The higher resolution VT levels don't have to be fully populated, so you only have to have high resolution images of the areas of interest. On a planet the size of the Earth, that yields a maximum resolution of about 10 meters/pixel for 512x512 tiles, and 1/8 of that or about 1 meter/pixel for 4Kx4K tiles.

Smaller features can be provided by using individual 3D models placed wherever desired, separately from the use of VTs.

The result looks much like what's in the video, except that it's drawn on a sphere. In addition to the surface texture, VT maps for specularity, bumps, nightlights and clouds are supported, too.

Unfortunately, generating VTs isn't as easy as it could be, although some scripts have been written to help.

Unlike WW, which uses DirectX and .NET and thus runs only under Windows, Celestia uses OpenGL and is available for Windows, MacOS and Linux.

p.s. large VTs can be put on the CelestiaMotherLode, which is hosted by ibiblio.

[Redrobes]

Thanks,

I am an OpenGL man myself. I know that WW used to be OpenGL running under OpenSceneGraph but they have apparently changed to C# with directX. God knows why - some external pressure I presume or that the programmer was only familiar with that API. They give some real tenuous reasons for it in their FAQ. Still, its up to them.

Interesting info on Celestia LODs. My ViewingDale is geared up for more arbitrary images instead of planets per se, so there are no fixed levels. It doesn't map onto a sphere like celestia and also its orthographic so no height field like WW or google earth.

If we get this map on WW then maybe afterwards ill come back and see what we can do with Celestia too and maybe host on the mother lode too. Its a free map after all.