If it is 20 mill. coordinates, it could be faster than 80 minutes, I
guess in the region of 10 minutes.
I would:
1 Combine 3+4 to something like (I assume ST_Multi is not needed) - this
avoids data duplication and one unnecessary transaction commit
SELECT randfield, (st_dump(ST_Union(f.geom)
I took the advice of Andreas and converted my code to using PostGIS.
And the speed difference is enormous.
The commands I've used:
// Import shapefile into PostGIS:
ogr2ogr -f PostgreSQL PG:"host=localhost user=..." fishnet.shp -gt
unlimited -lco GEOMETRY_NAME=geom -a_srs "EPSG:28992"
// Add rando
On Mon, 16 Jul 2018, Paul Meems wrote:
Thanks, Jon for your suggestion of GeoPandas.
Unfortunately, I'm not allowed to use new external dependencies.
Some timing:
1,677 shapes --> 0.3s
4,810 shapes --> 1.8s
18,415 shapes --> 21.4s
72,288 shapes --> 5min, 54s
285,927 shapes --> 25m
1,139,424 s
ST_Union in PostGIS should scale better than SQLite.
ST_Dump gives you singlepart geometries.
Best Regards
Andreas Oxenstierna
> 16 juli 2018 kl. 10:53 skrev Paul Meems :
>
> Thanks, Jon for your suggestion of GeoPandas.
> Unfortunately, I'm not allowed to use new external dependencies.
>
Thanks, Jon for your suggestion of GeoPandas.
Unfortunately, I'm not allowed to use new external dependencies.
I tried doing all steps in an SQLite file instead of using several
intermediate shapefiles. And I had some good results, so I created a script
dissolving an increasingly higher number of
lans for a Dissolve method on OGRLayer?
Jon
From: gdal-dev On Behalf Of Paul Meems
Sent: 29 June 2018 09:51
To: gdal-dev@lists.osgeo.org
Subject: Re: [gdal-dev] Dissolve large amount of geometries
Thanks Even for the suggestion.
We already thought about polygonizing the raster. But then I would
Thanks Even for the suggestion.
We already thought about polygonizing the raster. But then I would have
less control about where the vector geometry is created.
The squares/rectangle need to align with the tractor tracks/path.
The scenario I described is the first version: creating a fishnet. The
On jeudi 28 juin 2018 12:53:27 CEST Paul Meems wrote:
> Hi list,
>
> I've been working on this for months (off and on) and still no satisfying
> outcome.
> Either the process takes too long (multiple hours) or the result has
> invalid geometries.
>
> I want to try a different angle now. Instead o
Hi list,
I've been working on this for months (off and on) and still no satisfying
outcome.
Either the process takes too long (multiple hours) or the result has
invalid geometries.
I want to try a different angle now. Instead of asking technical questions
I want to explain what I try to do. Hopef
