[postgis-users] St_dumpAsPolygons function is too slow

[Elmehdi OUADOUD]

For example:

For a DEM raster X: 5261 Y: 4401 the vectorisation take 1 hour so I tintk 
that something is wrong on my querie

Le lundi 20 juillet 2015 15:18:42 UTC+2, Paul Ramsey a écrit :
>
> I would expect the vectorization of a raster to be fairly slow.
> Exactly how slow is another question.
>
> On Mon, Jul 20, 2015 at 6:14 AM, Elmehdi OUADOUD
> <ouadoud... at gmail.com <javascript:>> wrote:
> > Hi,
> >
> > I wonder know if the very very slow process is normal or i'm missing
> > something?
> >
> > thanks in advance
> >
> > Le mercredi 15 juillet 2015 10:11:46 UTC+2, Elmehdi OUADOUD a écrit :
> >>
> >> Hi All,
> >>
> >> I want to transfom a raster data to polygons but the process is too slow
> >> it takes 35 minutes.
> >> The querie i'm using :
> >>
> >>        select (ST_DumpAsPolygons(a.raster)).geom,
> >> (ST_DumpAsPolygons(a.raster)).val
> >>        from my_raster a
> >>
> >> Dimensions of my_raster
> >>
> >> X: 5261 Y: 4401
> >>
> >>
> >> I'm missing something or it's normal ?
> >>
> >>
> >
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