[GRASS-user] Re: v.in.ogr slowness with GRASS 6.4.1 on Linux

Markus Metz markus.metz.giswork at googlemail.com
Mon Jun 6 02:31:42 EDT 2011


On Mon, Jun 6, 2011 at 2:16 AM,  <Thomas.Adams at noaa.gov> wrote:
> Alexander,
>
> Good suggestions;I understand these are the kinds of suggestions I need to help me sort out what is going on. Did v.in.ogr change from, say, GRASS 6.3 and 6.4.1? In what ways?

>From 6.4.1 onwards, v.in.ogr uses a temporary vector to clean imported
polygons. The final output is cleaner and smaller compared to previous
versions. When importing polygons, boundaries are split in order to
speed up cleaning and merged again when cleaning is complete. The
speed improvement gained by adding this boundary splitting step is
considerable.

v.in.ogr may be a bit slower when importing points and lines, but it
should not be much slower. v.in.ogr from 6.4.1 onwards should be much
faster when importing polygons.

Can you make available a sample shapefile whose import takes more than
an order of magnitude longer than previous versions of GRASS?

BTW, using the -c flag is not recommended unless you really know what
you are doing.

Markus M

>
> Tom
>
> ----- Original Message -----
> From: Alexander Muriy <amuriy at gmail.com>
> Date: Sunday, June 5, 2011 5:53 pm
> Subject: [GRASS-user] Re: v.in.ogr slowness with GRASS 6.4.1 on Linux
> To: grass-user at lists.osgeo.org
>
>> > If I try to import a shapefile using GRASS 6.4.1 using v.in.ogr, it
>> takes
>> > more than
>> > an order of magnitude longer than previous versions of GRASS that I
>> > built and used.
>> >
>>
>> Maybe you're trying to import polygons with a topology cleaning? In that
>> case use "-c" flag in v.in.ogr (and/or "-t" flag).
>> What version of GDAL/OGR? (maybe problem in GDAL..)
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