[GRASS-user] Clipping rasters

[Nikos Alexandris]

Hanlie Pretorius wrote:

> I thought I created a clipped DEM by rasterising an irregular vector
> boundary and then using a mask to create the clipped DEM from a
> rectangular DEM.
> 
> For example:
> -----

#first, check and set your region of interest
g.region vect=border -pa

> # convert vector border to raster
> v.to.rast input="border" output="border" use="cat" type="area" layer=1
> value=1 rows=4096                                |
> 
> # set the mask to the raster border
> r.mask border

> # create the clipped DEM
> r.mapcalc
> 
> >dem_clipped=dem_full
> 
> # remove the mask
> r.mask -r
> -----
> 
> But it turns out I was wrong, the 'clipped' raster just contains NULL
> values outside of the border raster. What did I do wrong? Is there a
> better way to clip a raster to a vector boundary?

So, always check the region ;-). I think this is the best (and only?) way to 
clip.

Regards, Nikos