[GRASS-dev] Grass to postgis topology export performance

[Rémi Cura]

Hey,
thanks for your answer.

I uploaded a new test file of about the same number of line (32k),
also already topological (meaning in theory there is no need to split line,
just compute node, neighbourhood, and faces).

It is here : http://trac.osgeo.org/postgis/ticket/2695

About the command I used, I followed the wiki page on grass, I tried both
suggested methods:
I issued those with grass 7 svn, on windows, using the GUI to have a
terminal.

As I stated grass is extremely fast to build topology, and then the export
to postgis topology is already faster than using pure postgis topology, but
yet surprisingly slow compared to the grass internal.


v.in.ogr dsn="PG:host=localhost port=5433 dbname=street_gen user=postgres
password=??" layer=bdtopo.route out=test_postgis_import
v.out.postgis -l -2 input=route at T0111151 dsn="PG:host=localhost
dbname=street_gen port=5433 user=postgres password=??" olayer=test_layer -t



v.external.out dsn="PG:host=localhost dbname=street_gen port=5433
user=postgres password=??" options=topology=yes format=PostgreSQL
v.in.ogr dsn="....\route_utf8.shp" -t


Cheers,
Rémi-C


2014-04-01 13:42 GMT+02:00 Martin Landa <landa.martin at gmail.com>:

> Hi,
>
> 2014-04-01 11:43 GMT+02:00 Rémi Cura <remi.cura at gmail.com>:
>
> > Grass GIS is very fast to construct a topology over vectors (5 secs), and
> > then surprisingly slow in exporting this model to Postgis topology (145
> > sec).
> >
> > Is there a perticular reason for this? I tried to read the code, but
> > couldn't get to the sql querries.
> >
> > Also, in a more prospective way, could Grass import from geometry
> (shapefile
> > for example) then export to postgis topology be isolated (into an exe or
> a
> > lib?).
>
> could you post exact commands you run, or some sample data to play
> with. Thanks, Martin
>
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