[gdal-dev] ogr2ogr and WFS 2
Hernán De Angelis
variablestarlight at gmail.com
Tue Nov 30 00:34:15 PST 2021
Thank you, Jukka. I did that and worked. I also had another case where
it is important to get this right. It is when the total number of
features exposed by the service exceeds the maximum number of features
allowed to be fetched in one request (CountDefault). In this case it is
also important to set the paging to NO, in addition with an adequate
OGR_WFS_PAGE_SIZE so that the layer can be downloaded entirely, in
several pages, without hitting the limit.
Best
Hernán
Den 2021-11-30 kl. 08:59, skrev Rahkonen Jukka (MML):
>
> Hi,
>
> There is something about WFS 2 and paging in
> https://gdal.org/drivers/vector/wfs.html
>
> “Paging with WFS 2.0
>
> The WFS driver will automatically detect if server supports paging,
> when requesting a WFS 2.0 server. The page size (number of features
> fetched in a single request) is limited to 100 by default when not
> declared by the server. It can be changed by setting the
> OGR_WFS_PAGE_SIZE configuration option, or by specifying COUNT as a
> query parameter in the URL of the connection string.
>
> If only the N first features must be downloaded and paging through the
> whole layer is not desirable, the OGR_WFS_PAGING_ALLOWED configuration
> option should be set to OFF.”
>
> So by default normally GDAL goes to paging mode that makes it possible
> to read the whole featuretype, possibly restricted with BBOX or other
> filters but it should be possible to disable paging with --config
> OGR_WFS_PAGING_ALLOWED OFF. I would try that.
>
> -Jukka Rahkonen-
>
> *Lähettäjä:* gdal-dev <gdal-dev-bounces at lists.osgeo.org> *Puolesta
> *Hernán De Angelis
> *Lähetetty:* maanantai 29. marraskuuta 2021 12.43
> *Vastaanottaja:* gdal-dev at lists.osgeo.org
> *Aihe:* [gdal-dev] ogr2ogr and WFS 2
>
> Dear all
>
> I seem to have problems understanding how ogr2ogr interacts with WFS
> and hope someone would be able to clarify.
>
> I have this WFS:
>
> https://stationsregister.miljodatasamverkan.se/geoserver/stationsregistret/wfs?
>
> The capabilities document states that it supports WFS 1.0.0, 1.1.0 and
> 2.0.0.
>
> If I do:
>
> ogr2ogr -f GPKG test.gpkg
> "WFS:https://stationsregister.miljodatasamverkan.se/geoserver/stationsregistret/wfs?SERVICE=WFS&VERSION=1.0.0&REQUEST=GetFeature&TYPENAME=stationsregistret:active_site&MAXFEATURES=100
> <https://stationsregister.miljodatasamverkan.se/geoserver/stationsregistret/wfs?SERVICE=WFS&VERSION=1.0.0&REQUEST=GetFeature&TYPENAME=stationsregistret:active_site&MAXFEATURES=100>"
>
> I get a small and nice GPKG file very fast.
>
> But if I do:
>
> ogr2ogr -f GPKG test.gpkg
> "WFS:https://stationsregister.miljodatasamverkan.se/geoserver/stationsregistret/wfs?SERVICE=WFS&VERSION=2.0.0&REQUEST=GetFeature&TYPENAMES=stationsregistret:active_site&COUNT=100
> <https://stationsregister.miljodatasamverkan.se/geoserver/stationsregistret/wfs?SERVICE=WFS&VERSION=2.0.0&REQUEST=GetFeature&TYPENAMES=stationsregistret:active_site&COUNT=100>"
>
> It downloads the whole layer.
>
> This behaviour can be seriously impractical for services exposing a
> large number of features.
>
>
> Pay attention that if I do:
>
> curl
> "https://stationsregister.miljodatasamverkan.se/geoserver/stationsregistret/wfs?SERVICE=WFS&VERSION=2.0.0&REQUEST=GetFeature&TYPENAMES=stationsregistret:active_site&COUNT=100"
> <https://stationsregister.miljodatasamverkan.se/geoserver/stationsregistret/wfs?SERVICE=WFS&VERSION=2.0.0&REQUEST=GetFeature&TYPENAMES=stationsregistret:active_site&COUNT=100>
>
> it retrieves a short document fast with just 100 features. The same of
> course if I invoke the service using WFS 1.0.0 or 1.1.0.
>
>
> What is going on here? Is it me that I misunderstood something about
> how ogr2ogr is supposed to interact with WFS services?
>
> Using GDAL 3.4.0, released 2021/11/04. But the same behaviour was
> observed in 3.3.2.
>
>
> Thanks in advance for any clarification
>
>
> Hernán
>
>
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