best format for displacement maps

[lulu1315]

hello everyone.
I'm currently working on an earth like planet
I'm using blue marble next gen maps which are 21600*10800.
I will try adding displacement soon and I've got a houdini rat file so far , which I guess TG2 won't read.
what would be the best format/bitdepth for these kind of maps in TG2 ?
I'm working with 8GB of ram on winxp64.

thanks in advance
luc

[Oshyan]

I don't think the original displacement maps for Blue Marble are 16 bit or higher to begin with, so it would just be a waste of memory to use anything other than an 8 bit format. TGA, TIF, even JPG.

- Oshyan