[GRASS-user] v.in.ogr suddenly slow?

[Nikos Alexandris]

Giovanni Manghi wrote:
> > Hi all,
> > 
> > I just made a fresh install on my pc, Ubuntu 10.04 and GRASS 6.4 rc6
> > from the Ubuntugis repository.
> > 
> > It seems to me that v.in.ogr is quite slower if compared with my old
> > installation (6.4 rc5 on Ubuntu 9.04)
> > 
> > for example this
> > 
> > http://thematicmapping.org/downloads/TM_WORLD_BORDERS-0.3.zip
> > 
> > takes nearly 5 minutes and before it took much less.

Markus Metz wrote:
> Here it takes nearly 30 minutes with grass64, all versions, RC5 is not
> faster than RC6 or current svn. This vector is extremely dirty,
> boundaries of adjacent polygons don't match, resulting in about 2300
> overlapping areas and about 2400 spurious areas (gaps between adjacent
> polygons) equaling about 4700 erroneous areas for only 3775 input
> polygons. Import time was reduced to 4 minutes when snapping
> boundaries during import. With snapping during import and grass7, it's
> down to 1 min 46 sec and the result is topologically clean.
> 
> I would rather use another world boundary layer, e.g. UN FGGD from FAO
> geonetwork.

time v.in.ogr dsn=TM_WORLD_BORDERS-0.3.shp out=tm_world_borders_03
--%<---
3775 input polygons
Total area: 1.473113e+14 (8484 areas)
Overlapping area: 3.402229e+09 (2294 areas)
Area without category: 3.994093e+11 (2292 areas)

real    55m10.964s
user    54m50.060s
sys     0m8.040s
-->%---

:-O

Nikos