[GRASSLIST:7606] Re: Interior Buffers

[Maciek Sieczka]

Sorry Guys. All my fault. Stupid me displayed the output over the input, so 
I actually measured the distance between the interrior and exterior buffers 
of the output alone. All is fine with v.buffer, sorry for the mess. I wish I 
hadn't written that.

Dave

v.buffer might be usefull for your purpose, as it creates interior buffers 
(along with exterior) on line features, which you can obtain from you input 
rasters using r.to.vect, then v.type ... type=boundary,line.

Maciek

----- Original Message ----- 
From: "Maciek Sieczka" <werchowyna at epf.pl>
To: "Dave Sampson" <gis at watersheds.ca>; <GRASSLIST at baylor.edu>
Sent: Sunday, July 17, 2005 7:34 PM
Subject: [GRASSLIST:7574] Re: Interior Buffers


> 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
>