[GRASSLIST:7574] Re: Interior Buffers

[Maciek Sieczka]

David

From: "Dave Sampson" <gis at watersheds.ca>

> using r.buffer how might I perform an interior buffer. That is take the 
> outside of a raster clump (from r.clump) and make concentric internal 
> buffers at 100, 200, 300 meters etc?.

Accidently I have found the functionality you are interested in in v.buffer, 
which seems to be a undocumented feature or a bug.

Anyway: if the input for v.buffer is a *closed* *line* (not the area), then 
the output is an "internal buffer" :) area polygon, which is of about 
*twice* the extent you provide in option "buffer=".

I have reported it as a bug http://intevation.de/rt/webrt?serial_num=3427.

After rethinking it, I'm not sure what to think. It seems a kind of bug on 
one hand, especially that the "internal buffer" size is 2 x the buffer 
required, and a cool functionality on the other.

The best IMHO would be to extend v.buffer to be able to create such 
"internal buffers" in a controlled and documented way. Any chances? What do 
others think?

Maciek