[GRASS-dev] Large Polygon-datasets

[Radim Blazek]

On 5/9/06, Hamish <hamish_nospam at yahoo.com> wrote:
> > I have a very large dataset containing about 300.000 polygones which I
> > would like to import into GRASS using v.in.ogr
> >
> > Is there a possibility to not build the topology during import, but
> > afterwards. It runs nor about several hours now and does not provide
> > more information than
> > Importing 300000 map features...
> >
> > and nothing more. The maschine is very slow in response using the
> > mouse.
> >
> > Does anybody have some experience in using this kind of datasets?
> > Thanks for any suggestions how to import the data.
>
>
> Yes, I have seen this and IIRC there was a Florida Coastline import with
> the same problem.
>
> In all cases the polygons were all unbroken polygons with only one end
> node breaking a single boundary line.
>
>
> At the time, Radim wrote:
> > Now I have just one idea, because the areas are probably isolated,
> > it could be that exist one BIG boundary around all the map
> > (I thing that something like that exists in ArcInfo),
> > in that case, when this boundary is processed, it selects
> > lines which could intersect it by bounding box, in that case ALL
> > lines, and to check intersection of ALL segments of that BIG line
> > with ALL segments of ALL other lines can take a very long time.
>
> I think this case is why he wrote v.split.

It must go to v.in.ogr.
v.in.ogr -c + anything != v.in.ogr

Radim


> here we go,
>  http://thread.gmane.org/gmane.comp.gis.grass.user/7391/focus=7394
>  http://thread.gmane.org/gmane.comp.gis.grass.devel/7417
>  http://article.gmane.org/gmane.comp.gis.grass.devel/7400
>  http://grass.itc.it/pipermail/grassuser/2005-April/028518.html
>  http://grass.itc.it/pipermail/grass-dev/2005-March/017745.html
> ...
>
>
> Hamish
>
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