[GRASSLIST:5141] Re: Raster crop/mask.

[H. Bowman]

> Now I am trying to determine how I might be able to draw a polygon and
> import one dxf (known) then use that polygon as a mask or cropping
> line then in turn right out the area still visible of the TIFF.

read the man page for r.in.poly.  I think making a poly file and importing it, then using r.mask and r.mapcalc croppedTIFF=importedTIFF would do the trick.