Hi Rado
[cc to grass5]
On Wed, Feb 21, 2001 at 03:12:41AM -0600, Rado Bonk wrote:
Hi Markus
r.reclass.are does the job, but after eliminating specified regions, there
are wholes (NO DATA )in the geographic region raster. The regions smaller
than specified value have to be appended to neighboring regions,
based on some reasonable algorithm (for example, based on the
length of its common boundary > they will be attached to region
with longest common boundary). Deleting the regions doesn't solve the
problem.
So you need a "filling hole" algorithm, what you wrote about inwards
buffering. Now I understand. This is what I am dreaming of as well 
Justin: Once we have been talking about this how to fill NULL holes in
a raster map. It seems we need it now.
Markus
Rado Bonk
Geography and Geology
UNO, Omaha, NE 68182-0199
rado@cosmos.unomaha.edu
http://rbonk.host.skOn Wed, 21 Feb 2001, Markus Neteler wrote:
> Hi Rado,
>
> On Wed, Feb 21, 2001 at 02:22:24AM -0600, Rado Bonk wrote:
> > Hi GRASS users,
> > After mulptiply overlay operations, there are several
> > (hundreds) raster regions with the area too small for analysis. I would
> > like to eliminate these regions and append them to the adjacent regions
> > based on the length of its common boundary (that would be the best).
> > r.reclass.area script does a nice job with elimination of these regions by
> > assigning the area of the smallest region, and deleting all regions with
> > area smaller than assigned value. (Markus, there is an error in
> > line 9, missing || operand, see correct line at the end of the message).
> Thanks for notification. I had fixed it recently and also another script
> bug.
> You can catch the latest from (web)CVS.
>
> > The task can be solved by exporting raster regions into vector, and than
> > using vector algebra in some of the desktop mapping systems. However, I
> > would like to avoid this, and I would like to use raster data
> > format. Maybe some filter would help.
> >
> > There was similar question a time ago concerning "inward
> > buffering" operation with no response.
>
> Sorry, I don't get the problem. If r.reclass.area does the job, what's left?
>
> Markus
>
--
Markus Neteler * University of Hannover
Institute of Physical Geography and Landscape Ecology
Schneiderberg 50 * D-30167 Hannover * Germany
Tel: ++49-(0)511-762-4494 Fax: -3984
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