[GRASS-dev] interferring ovewrite flags [was: [bug #5167] (grass) v.patch: -a(ppend) issues]

Hamish hamish_nospam at yahoo.com
Sun Oct 1 22:08:49 EDT 2006

Michael Barton wrote:
> Is having both -o and --o a problem?
> The reason I ask is that --o, by design, doesn't show up in the
> module/script GUI. For r.mask, much of the time, the user will simply
> want to overwrite the existing MASK file, to avoid the annoyance of
> having to run g.remove each time (note the MASK file created by r.mask
> is a reclass of a real raster file, so there is little loss if it is
> deleted).
> So in this case, I'd prefer to have an overwrite option easily
> accessible to a user. How best to do this?

be careful with using r.mask or r.mapcalc to overwrite a MASK. If the
old mask is still present when the new one is created, it will be an
additive replacement, not a full replacement. This can be very useful
for "building up" a MASK map, but also cause lots of problems if you
aren't expecting it.

I'm not exactly sure how r.reclass works (thus r.mask script too), but
it will work like this if it reads raster data row by row.


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