[GRASS-user] elimination of holes in a vector layer

GRASS GRASS user
1

Dear list,

I got a polygon layer, in which there are some holes.

Is there a way to control the elimination of those holes, ie
eliminates holes smaller than a given size, and keep the others (that
are considered as significant by the user).

Cheers,

Pierre

--
Scientist
Landcare Research, New Zealand

2

On Tue, Jan 11, 2011 at 12:20 AM, Pierre Roudier
<pierre.roudier@gmail.com> wrote:

Dear list,

I got a polygon layer, in which there are some holes.

Is there a way to control the elimination of those holes, ie
eliminates holes smaller than a given size, and keep the others (that
are considered as significant by the user).

v.clean tool=rmarea thresh=X removes all areas, both holes and other
areas, <= X, X is in squared map units or square meters for latlon .

Just for clarification, in GRASS vector topology, holes are areas
without a centroid located within other areas.

If you want to remove small holes only, you can
1. run v.clean as above
2. upload area size to the attribute table in the original vector
3. extract all areas <= X from the original vector
4. patch the cleaned and the extracted vectors
5. clean the patched vector with v.clean tool=bpol,rmdupl

HTH,

Markus M

3

Hi,

2011/1/12 Markus Metz <markus.metz.giswork@googlemail.com>:

If you want to remove small holes only, you can
1. run v.clean as above
2. upload area size to the attribute table in the original vector
3. extract all areas <= X from the original vector
4. patch the cleaned and the extracted vectors
5. clean the patched vector with v.clean tool=bpol,rmdupl

probably we could implement this as v.clean tool=rmhole ?

Martin

--
Martin Landa <landa.martin gmail.com> * http://geo.fsv.cvut.cz/~landa