> There are various types of so-called 'DEM' data formats which need
> different conversion programs.  A lot of them are in a quite simple ASCII
> form, but some are more complicated.  Nearly all are 16 bit data in the
> original so the 8 bit you get are probably result of the conversion.  

I'm having to deliberately convert them to 8 bit, since that's the only 
way I have of editing them after I convert them.  If I had image editing 
software that could read and manipulate 16bit grayscale images, I'd 
start from there and probably not have the problem at all.  But so far, 
I've been unable to find anything that can manipulate 16bit grayscale 
images.  I tried UTSCSA's ImageTool 2.0, but it can't handle the large 
file sizes needed.

So the lack of a 16bit image editor is the reason why I have to go to 8 
bit, edit, then convert to 16, using bicubic interpolation while 
increasing the pixel scale to smooth out the results.  But it's not 
smoothing enough.  So I need something that can either edit the 16bit 
images, or at least run a good smoothing algorithm on the converted 
16bit image.

I'm assuming that if I could get the full dynamic range of 16bit 
grayscale, my stepping issue should go away.  If not, well, then I'm 
back to the drawing board.

Post a reply to this message