[GRASS-user] Re: Exporting Vector data to SHP (v.out.ogr)- takes a lot of time

Luis wrote:
1- My orioginal raster file has the following:

...

Registering primiti 907000
907256 primitives registered

900k is a lot, but not crazy.

3527832 vertices registered
Building areas...
321179 areas built

300k areas is not small, but it is not huge either.
...

Exporting 321179 areas (may take some time)...

And after 20 minutes it seems freezed

wait longer... maybe hours or overnight.
export to shapefile with v.out.ogr is known to be
quite slow.

are you sure it is frozen? check in process monitor
("top" on mac or linux, ctrl-alt-del on Windows)
if cpu usage by v.out.ogr is 100%, and how much
memory it is using. if it is frozen cpu will be 0%,
if it is still working cpu will be 100%.

It this too much polygons?

perhaps. maybe resample raster to a coarser grid
or try running v.build.polylines on the vector map
prior to export.

Hamish

Hi,

2010/11/12 Hamish <hamish_b@yahoo.com>:

Registering primiti 907000
907256 primitives registered

900k is a lot, but not crazy.

you can also try GRASS 7.

Martin

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

Well in this case I’m building my Msc Thesis on GRASS (interfaces+functions+modles) and tyhat would mean loose some part of my work So, and since GRASS6.4.0 was expected to export this data, what can I do? is this a lack-of-memory problem? or sometyhing that other users haver already experienced?
Thanks
Luis

On Mon, Nov 15, 2010 at 7:29 AM, Martin Landa <landa.martin@gmail.com> wrote:

Hi,

2010/11/12 Hamish <hamish_b@yahoo.com>:

Registering primiti 907000
907256 primitives registered

900k is a lot, but not crazy.

you can also try GRASS 7.

Martin


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

On Mon, Nov 15, 2010 at 10:14 AM, Luis Lisboa <luislisboa1975@gmail.com> wrote:

Well in this case I'm building my Msc Thesis on GRASS
(interfaces+functions+modles) and tyhat would mean loose some part of my
work So, and since GRASS6.4.0 was expected to export this data, what can I
do? is this a lack-of-memory problem?

Hamish suggested to check if v.out.ogr is really frozen, i.e. it
should keep the cpu busy. As long as it keeps the cpu busy, everything
is fine and you just have to wait it out. Of course you can also check
how much memory v.out.ogr currently uses. If v.out.ogr goes into swap
space, it will take a very long time. 213680 areas is a lot, and it
will most probably take more than 10 minutes, rather give it a few
hours or run it overnight. It will also require a bit of disk space,
several 100MB, just to be sure you could check that there is enough
disk space where the shapefile is supposed to be written to.

Since the vector to be exported is a converted raster, apparently
without further modification, why not exporting the raster?

Martin Landa:

you can also try GRASS 7.

v.out.ogr in GRASS 7 is probably not much faster, and you would have
to rebuild topology first which will most probably also take more than
10 minutes for 213680 areas...

Markus M

Am 15.11.2010 10:47, schrieb Markus Metz:

Since the vector to be exported is a converted raster, apparently
without further modification, why not exporting the raster?

...I thought the same. What do you want to do?

Maybe you can tile the raster and create some or many vector maps?

Achim