[Qgis-user] clip geojason QGIS

[Charles Dixon-Paver]

>  Convert it to a geopackage first -- geojson is a HORRIBLE format for
large datasets like this, as it's completely unoptimised and has no spatial
index

Just want to add that shapefile itself has size limitations and is not a
good format for these types of large datasets (or anything really), so I
definitely recommended using gpkg.

On Thu, 22 Oct 2020 at 03:52, Nicolas Cadieux <njacadieux.gitlab at gmail.com>
wrote:

> Hi,
>
> If the clipping operations takes too much time, you could try a spatial
> query. Once you have a field with the states for each building, then you
> can split the file with that field. This may, or may not be faster. Maybe
> also be a problem with building sitting on the border.
>
> Nicolas Cadieux
>
> > Le 21 oct. 2020 à 20:28, Nyall Dawson <nyall.dawson at gmail.com> a écrit :
> >
> > On Thu, 22 Oct 2020 at 10:23, Nyall Dawson <nyall.dawson at gmail.com>
> wrote:
> >>
> >>> On Thu, 22 Oct 2020 at 10:15, <Iain at jcis.net.au> wrote:
> >>>
> >>> Nyall,
> >>>
> >>> Thanks for your quick reply. Would I load it first and then save the
> layer as a geopackage to do that? Or do I have to do something more
> elaborate?
> >>
> >> I'd do it from the QGIS browser panel -- right click on the geojson
> >> file and save as.
> >
> > Just to clarify -- that's the "export" option, not "save as".
> >
> > Nyall
> >
> > That'll save some of the initial time required to
> >> load this into QGIS.
> >>
> >> (alternatively the fastest way to convert would be to use ogr2ogr
> >> directly from the command line, if you're comfortable with that!)
> >>
> >> Nyall
> >>
> >>>
> >>> Cheers
> >>>
> >>> Dr Iain Stuart
> >>> JCIS Consultants
> >>> P.O. Box 2397
> >>> Burwood North
> >>> NSW, 2134
> >>>
> >>> (02) 9701 0191
> >>> (0413) 380116 (m)
> >>>
> >>> -----Original Message-----
> >>> From: Nyall Dawson <nyall.dawson at gmail.com>
> >>> Sent: Thursday, 22 October 2020 10:41 AM
> >>> To: Iain at jcis.net.au
> >>> Cc: qgis-user <qgis-user at lists.osgeo.org>
> >>> Subject: Re: [Qgis-user] clip geojason QGIS
> >>>
> >>> On Thu, 22 Oct 2020 at 09:33, <Iain at jcis.net.au> wrote:
> >>>>
> >>>> It seems that Microsoft (of all people) is creating this database of
> building shapes for the known universe. They recently completed Australia
> and made it available. It is in a zipped geojason file – a format that I
> have no idea about.
> >>>>
> >>>>
> >>>>
> >>>> I have loaded it to QGIS and it is huge. It took over 30min to load
> and it takes about 10min to redraw every time and I am not running it on a
> Pentium 4 with 8bits of ram either.
> >>>
> >>> Convert it to a geopackage first -- geojson is a HORRIBLE format for
> large datasets like this, as it's completely unoptimised and has no spatial
> index. Effectively on every redraw QGIS is having to loop through the
> entire 6gb geojson file every time! ouch....
> >>>
> >>> Nyall
> >>>
> >>>
> >>>
> >>>>
> >>>>
> >>>>
> >>>> I would like to clip the data to the states of Australia which I have
> a vector files or maybe regions in order to get the dataset smaller so it
> can be more usable.
> >>>>
> >>>>
> >>>>
> >>>> Can you clip geojason files ? or would I have to covert them into
> something like shapefiles? Any ideas on a workflow to do this?
> >>>>
> >>>>
> >>>>
> >>>> BTW I am running an I7-8700 with 16mb RAM and a NVIDIA Quadro P2000.
> >>>>
> >>>>
> >>>>
> >>>> Cheers
> >>>>
> >>>>
> >>>>
> >>>> Dr Iain Stuart
> >>>>
> >>>> JCIS Consultants
> >>>>
> >>>> P.O. Box 2397
> >>>>
> >>>> Burwood North
> >>>>
> >>>> NSW, 2134
> >>>>
> >>>>
> >>>>
> >>>> (02) 9701 0191
> >>>> (0413) 380116 (m)
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
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> >>>
> >>>
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