[GRASS-user] v.overlay stops running

Hello!

I am trying to overlay two huge polygons.
After some time v.overlay dies or stops running:

Copying ainput lines ... 100%
Collecting input attributes ...
-----------------------------------------------------------------------------
Copying binput lines ... 100%
Collecting input attributes ...
-----------------------------------------------------------------------------
Building partial topology ...
-----------------------------------------------------------------------------
Breaking lines ...
Intersections: 370143
-----------------------------------------------------------------------------
Removing duplicates ...
Duplicates: 26
-----------------------------------------------------------------------------
Cleaning boundaries at nodes ...
Modifications: 0
-----------------------------------------------------------------------------
Attaching islands ...
Building topology ...
Building areas: 31%

then it stays at 31% for more than 30min. I suppose it has stopped. When I look
at the files in directory I don't see any change on them for the same period.

Why does it stop like that?

Thanks and greetings,
Tim

Tim Michelsen wrote:

I am trying to overlay two huge polygons.
After some time v.overlay dies or stops running:

...

-------- Attaching islands ...
Building topology ...
Building areas: 31%

then it stays at 31% for more than 30min. I suppose it has stopped.
When I look at the files in directory I don't see any change on them
for the same period.

Why does it stop like that?

this may or may not work, but you might try running the big polygons
through "v.split vertices=5000" first.

see the "v.out.ogr" section of doc/vector/TODO in the source code for
the explanation:

"It would be useful to split long boundaries to smaller
pieces. Otherwise cleaning process can become very slow because
bounding box of long boundaries can overlap large part of the map (for
example outline around all areas) and cleaning process is checking
intersection with all boundaries falling in the bounding box."

Radim wrote v.split to work around this issue.

Hamish

Hello,
thanks for your help.

this may or may not work, but you might try running the big polygons
through "v.split vertices=5000" first.

I can't find this command.
It seems that this is only in CVS so far?
I am using a GRASS 6.0.2 on Ubuntu Linux.

Greetings,
Tim

The current stable version is 6.2. I recommend that you at least upgrade to
that.

Michael

On 2/15/07 7:45 AM, "Tim Michelsen" <timmichelsen@gmx-topmail.de> wrote:

Hello,
thanks for your help.

this may or may not work, but you might try running the big polygons
through "v.split vertices=5000" first.

I can't find this command.
It seems that this is only in CVS so far?
I am using a GRASS 6.0.2 on Ubuntu Linux.

Greetings,
Tim

__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics and Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

Michael Barton wrote:

The current stable version is 6.2.

It's 6.2.1 actualy.

I recommend that you at least upgrade to that.

Absolutely.

Maciek