[GRASS-user] combining tiles

[Tyler Smith]

On Wed, Feb 07, 2007 at 11:38:27AM +1300, Hamish wrote:
> Gerald Nelson wrote:
> > > Why not use r.patch in grass to combine them,
> 
> 
> tips o'the day:
> 
> This command will turn -9999s into NULLs:
>   r.null setnull=-9999
> 

Thank you, thank you, thank you! 

Either this is a very common problem, or you were reading my
mind. I've been trying to get 19 maps coloured properly, and I'd
realized that none of the automatic settings were going to work
because of the -9999 values skewing all the schemes. I hadn't yet
figured out how to change those values to NULLs. I have exported my
tiles to ESRI ascii grids, and the -9999 values don't appear to have
influenced the subsequent analysis in Maxent. But it was getting very
tedious hand-editing the colour tables.

Thanks!

-- 
Regards,

Tyler Smith