[GRASS5] r.random and topology: building areas etc?
Markus Neteler
neteler at itc.it
Tue Jun 28 03:55:27 EDT 2005
Hi,
the problem below is still unsolved... do we need to build full topology
for points?
Related to that: Exporting points with v.our.ogr is very slow,
do we have/need to integrate spatial index for points?
Example: Exporting 120k points takes 2 minutes on a 2.5GHz machine
to reach only 1 percent...
grass61 ~/grassdata/spearfish60/user1/
g.region rast=elevation.10m -p
r.random elevation.10m vect=random120k n=120000
time v.out.ogr random120k dsn=random120k.shpolay=random120k type=point
Exporting 120000 points/lines...
real 233m18.811s
user 230m38.497s
sys 1m41.950s
Line export is really fast compared to points export.
Any ideas?
Markus
On Thu, Jun 23, 2005 at 04:50:30AM +0200, Markus Neteler wrote:
> Hi,
>
> I was generating 3.x mio points to test v.in.ascii and discovered,
> that r.random build full topology which is just a waste of time.
> How to change that?
>
> r.random elevation.10m n=3200000 vector_output=random3_2mio
> Collecting Stats ... 100%
> Writing site file [random3_2mio] ... 100%
> Erzeuge Topologie ...
> 3200000 primitives registriert
> Building areas: 7%
> ...
>
> Should we use Vect_build_partial()?
>
> Markus
>
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