[GRASS-user] combining tiles

[Gerald Nelson]

Why not use r.patch in grass to combine them, use g.region to set a smaller region and export, or create a mask of the smaller region and have the mask set when you use r.patch?

Jerry

---- Original message ----
>Date: Mon, 5 Feb 2007 17:59:44 -0400
>From: Tyler Smith <tyler.smith at mail.mcgill.ca>  
>Subject: [GRASS-user] combining tiles  
>To: grass help <grassuser at grass.itc.it>
>
>Hi,
>
>I'm a brand-new Grass user. I'm working on an ecological niche
>modelling project, for which I'm using the WorldClim bioclimatic
>tiles. They are distributed as .bil files, which I've figure out how
>to get into Grass. I need to convert them to ESRI ascii grid formats,
>which I can also do.
>
>My problem is that I need the data from parts of four separate
>tiles. I've set up my location so that it will clip the appropriate
>section as I export the grids into ascii format, but the only way I
>can figure out to get the data into a single grid is to export each of
>the four tiles separately, manually cut off the headers, import the
>matrices into R, cbind() or rbind() them together, write.table them back
>to a file, and then put the header back on. This works, but it's
>tedious! 
>
>There must be some Grass function to do this all in one step?
>I've searched google and the on-line manuals with no luck, but
>unfortunately I don't have access to the recommended published book
>(waiting for the new edition before I buy it for myself).
>
>Any help would be appreciated!
>
>-- 
>Regards,
>
>Tyler Smith
>
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Gerald Nelson
Professor, Dept. of Agricultural and Consumer Economics
University of Illinois, Urbana-Champaign
office: 217-333-6465 
cell: 217-390-7888
315 Mumford Hall
1301 W. Gregory
Urbana, IL 61801