DEm generation from raw data

[Sheilah Nolan]

Hello,

The easiest method of generating a raster DEM is to use
s.surf.idw.  Make sure that your ASCII file is in your
site_lists directory and in the
correct format:

name|filename
desc|your id notes
easting|northing|elevation

You can also generate a raster map of DEM data using s.surf.tps or
s.surf.2d, depending on your version of GRASS.  This is trickier
and will require a fair bit of playing around, but yields a better
(more true to your data) product.

I assume that these DEM's can be used as input to r.watershed, but
have never tried this.

Good luck.

Sheilah


********************************************************************************

Sheilah C. Nolan                          email:  snolan at ulysses.sis.ualberta.ca
Research Agronomist                       Phone:  (403) 422-6530 
Conservation and Development Branch       Fax:    (403) 422-0474 
Alberta Agriculture, Food and Rural Development
#206, 7000 - 113 Street
Edmonton, Alberta T6H 5T6 CANADA

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> 
> Hi,
> 
> I have raw elevation data which is in ACSII format:
> 	easting northing elevation
> 
> Which command would be appripriate to tansfer this file to grass accepted
> raster data format ? so that I could generate a gridded DEM and derive a
> driange network using related grass command, such as r.watershed.
> 
> Thanks in advances,
> 
> Vincent
> 
> Vincent Tao
> The University of Calgary
> tao at arc.ab.ca
>