640MB Earth tif to be used with Celestia...how?

[alegator]

I went to the following site :
ftp://visibleearth.nasa.gov/pub/EARTHVIZ/
and downloaded Hires tifs of the earth divided into 2 files: a 400MB tif of the east and a 240MB tif of the west.
I tried merging the two with Photoshop to create a single 640MB tif of the whole earth surface, but when I define the image size photoshop won't allow.
Can anyone tell me how to combine the two into a single 640MB tif so to use it with Celestia? Thanks!

[Sum0]

I'm not sure, but I don't think Photoshop allows you to have images larger than a certain size. Also remember that 640mb doesn't go well with a 128mb graphics card, so unless you manage to reduce the size it probably isn't worth the bother.

[Redfish]

You can use the gimp download it somewhere, just search for it on google.

That program allows any size image. But i tried it myself too and you'll need 3.5 gigs of memory to load the total of both files. And i don't have that amount of memory. so when it starts to swap you can go to bed and come back the next morning. It's totally unusable.

Pixel told me that there are programs that let you join both files without loading them first, but i don't know which programs these are.

[selden]

The NetPBM utilities work a scan-line at a time, so they can manipulate quite large images. They're available on SourceForge or you can use Google to find them. They don't have a GUI. You have to use a command-line window. (I use Cygwin.)

NetPBM includes many format conversion utilities. The various image manipulation programs only work on its native uncompressed format, so you'll need plenty of free disk space.

[John Van Vliet]

GIMP will do it but to use the image in celestia it will need to be converted to .png and scalled down to 8192x4096 to run you will also have to remove the spectrial map from the image and past it in a new image then install the two images in celestia

you may as well just download the smaller image of (the whole earth)
enen then this one is to big