ArcInfo to Grass conversion

[Tom Moore]

In grass.user you write:

>I need to import 126, 1:20,000 scale forest stand maps (each covers 
>10km x 10km) into GRASS.  All I need in each cell is the unique stand 
>number (I've renumbered in ARC/INFO so I have unique numbers from 1 
>to 56,312).
 
>I've been reading about v.in.arc, but ungenerating all those maps and 
>rebuilding the topology and then rasterizing on the GRASS side seems 
>a bit much (perhaps those that have done it could assure me that it 
>is not too bad, or warn me of watch-out-for's).
 
>The other alternative is to use arc/info's POLYGRID command and 
>output and ASCII file and then use r.in.ascii.  Unfortunately, the 
>file formats aren't quite the same, but I could write code if 
>required to do the transfer (I'm hoping that somebody has already 
>done that -- or there is an easier way).

Steve:

The ARC and GRASS raster file formats are really not all that different.
If you already have topologically correct ARC polygon files, 
I have found the easiest thing is to do a POLYGRID, convert the
grid files to ascii using GRIDASCII, and then make some minor modifications
using a text editor.   If you wanted to automate this I'm sure it could
be done efficiently with a very short perl script.

Tom.
--
Tom Moore R.P.F.                                tmoore at pnfi.forestry.ca
Petawawa National Forestry Institute            
Canadian Forest Service, Box 2000, Chalk River  +1 (613) 589-3048
ONT K0J 1J0  CANADA                             +1 (613) 589-2275 telefax