[mapserver-users] Mapserver doesn't send good filter to postgis
Stephen Woodbridge
woodbri at swoodbridge.com
Mon Jan 26 13:10:29 PST 2015
On 1/26/2015 2:12 PM, Steve.Toutant at inspq.qc.ca wrote:
> Thanks for your explanation Stephen.
> I'm sure there were good reasons to do that, but it is a weird way of
> filtering.
It is a legacy issue the RFC 91 I think is trying to clean up. Mapserver
started with rasters and shapefiles, so everything had to be done in
mapserver. As it grew to support more data sources things have changes
and we are trying to push this kind of filtering back into the data
sources where it can be done efficiently, while still allow other data
sources that do not support the native filtering to work also work by
having a generic filing ability still built into mapserver.
Steve W
> I Cannot use the bbox of the window but as you suggest, passing the bbox
> of the geometry could be a workaround.
>
> If someone as an idea on how we could pass the bbox of the geometry to
> mapserver or any other ideas it would be much appreciated.
>
> Is this issue will really be improved in mapserver 7 for postgis and
> oracle? When is it scheduled?
>
> thanks again for your help!
>
> steve
>
>
>
>
> *Stephen Woodbridge <woodbri at swoodbridge.com>@lists.osgeo.org*
> Envoyé par : mapserver-users-bounces at lists.osgeo.org
>
> 2015-01-26 11:31
>
>
> A
> mapserver-users at lists.osgeo.org
> cc
>
> Objet
> Re: [mapserver-users] Mapserver doesn't send good filter to postgis
>
>
>
>
>
>
>
>
>
>
> Steve T.,
>
> mapserver gets back all the geometries from postgis and then filters
> them in mapserver against the geometry.
>
> Mapserver passes the BBOX for the mapfile to postgis as you noticed
> which is not very efficient, but you can override that to the BBOX of
> the window using the BBOX substitution variable in the SQL, but this
> might not be what you want if you geometry is off screen.
>
> I'm not aware of any way to pass the BBOX of the geometry.
>
> Steve L - can we do this?
>
> So currently, your wfs requests are getting filtered against the
> geometry. And there is room for efficiency improvements.
>
> -Steve W
>
> On 1/26/2015 11:15 AM, Steve.Toutant at inspq.qc.ca wrote:
> > sorry I'm confused, perhaps I misunderstand what you explained. I don't
> > understand what you mean by "MapServer does use the supplied geometry,
> > it’s a matter of where the filter is applied – the database or in
> > MapServer"
> >
> > In mapserver log I see
> >
> > FLTLayerApplyPlainFilterToLayer(): ([shape] within fromText('POLYGON
> > ((-8081644.2511243997141719 5835062.5699599999934435,
> > -8081707.5505384001880884 5834980.1612889003008604,
> > -8081638.2794815003871918 5834913.2788891997188330,
> > -8081533.1785677000880241 5834988.5215889001265168,
> > -8081644.2511243997141719 5835062.5699599999934435))'))
> >
> > So this is good, but
> > A few lines later in the mapserver log, I see that it is not sending the
> > supplied geometry as filter, it is sending the extent of the mapfile
> > select ....... where geom_p && ST_GeomFromText('POLYGON((-9239517
> > 5465442,-9239517 9349764,-5565974 9349764,-5565974 5465442,-9239517
> > 5465442))',3857);
> >
> > So it received the supplied geometry, but it is not using it....
> >
> > If only BBOX can be used as a spatial operator, it is not good for our
> > needs. We really need to know what features are inside a user defined
> > polygon.
> >
> >
> >
> >
> > *"Lime, Steve D (MNIT)" <Steve.Lime at state.mn.us>*
> >
> > 2015-01-26 10:56
> >
> >
> > A
> > "Steve.Toutant at inspq.qc.ca" <Steve.Toutant at inspq.qc.ca>
> > cc
> > "mapserver-users at lists.osgeo.org"
> <mapserver-users at lists.osgeo.org>
> > Objet
> > RE: [mapserver-users] Mapserver doesn't send good
> filter to postgis
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > MapServer does use the supplied geometry, it’s a matter of where the
> > filter is applied – the database or in MapServer. This isn’t a new
> > limitation so others may have more experience with workarounds. Maybe
> > try also setting a bbox in the filter based on the bbox of the geometry?
> >
> > Steve
> >
> > *From:* Steve.Toutant at inspq.qc.ca [mailto:Steve.Toutant at inspq.qc.ca] *
> > Sent:* Monday, January 26, 2015 9:38 AM*
> > To:* Lime, Steve D (MNIT)*
> > Cc:* mapserver-users at lists.osgeo.org*
> > Subject:* RE: [mapserver-users] Mapserver doesn't send good filter to
> > postgis
> >
> > I understand the objective of rfc 91, but the most common use case would
> > be to pass the supplied geometry.....
> >
> > If mapserver doesn't use the supplied geometry, that means that it
> > doesn't support spatial filtering.
> >
> > Our data covers the whole country, not using the supplied geometry means
> > we can't use mapserver as a wfs server....
> >
> > Is there something we can do about it? A workaround we could use?
> >
> >
> > *"Lime, Steve D (MNIT)" <**_Steve.Lime at state.mn.us_*
> > <mailto:Steve.Lime at state.mn.us>*>*
> >
> > 2015-01-26 10:14
> >
> >
> > A
> > "_Steve.Toutant at inspq.qc.ca_
> <mailto:Steve.Toutant at inspq.qc.ca>"
> > <_Steve.Toutant at inspq.qc.ca_ <mailto:Steve.Toutant at inspq.qc.ca>>,
> > "_mapserver-users at lists.osgeo.org_
> > <mailto:mapserver-users at lists.osgeo.org>"
> > <_mapserver-users at lists.osgeo.org_
> > <mailto:mapserver-users at lists.osgeo.org>>
> > cc
> >
> > Objet
> > RE: [mapserver-users] Mapserver doesn't send good
> filter to postgis
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > It’s a limitation in older versions of MapServer where specific backend
> > optimizations were scattered about the WMS/WFS code. Most of those
> > optimizations address the most common use cases – I guess this wasn’t
> > one of them. It’s surprising that at worst the extent of the supplied
> > geometry isn’t passed (I see a comment in the WFS code about this). The
> > specific filter intersection test is applied on the MapServer side – the
> > results are correct, performance can suffer though.
> >
> > This is being addresses in MapServer 7.0 where more complete filter
> > translation functions are being supported (RFC 91).
> >
> > Steve
> > *
> > From:* _mapserver-users-bounces at lists.osgeo.org_
> > <mailto:mapserver-users-bounces at lists.osgeo.org>
> > [_mailto:mapserver-users-bounces at lists.osgeo.org_] *On Behalf Of
> > *_Steve.Toutant at inspq.qc.ca_ <mailto:Steve.Toutant at inspq.qc.ca>*
> > Sent:* Monday, January 26, 2015 8:55 AM*
> > To:* _mapserver-users at lists.osgeo.org_
> > <mailto:mapserver-users at lists.osgeo.org>*
> > Subject:* [mapserver-users] Mapserver doesn't send good filter to postgis
> >
> > Sorry my first post was with an inapprpriate title......
> >
> > I'm using mapserver 6.4.1 and postgis 2.1
> >
> > using OpenLayers 2.13.1 I draw a small polygon that I use for a within
> > spatial filter of a WFS getfeature request. The problem is that
> > mapserver is not sending this polygon to postgis, it is sending the
> > extent of the mapfile as filter...
> >
> > The wfs POST Request (created and send by OpenLayers client)
> > <ogc:Filter
> >
> xmlns:ogc="_http://www.opengis.net/ogc_"><ogc:Within><ogc:PropertyName>msGeometry</ogc:PropertyName><gml:Polygon
> > xmlns:gml="_http://www.opengis.net/gml_"
> >
> srsName="urn:ogc:def:crs:EPSG::3857"><gml:exterior><gml:LinearRing><gml:posList>-8081644.2511244
> > 5835062.56996 -8081707.5505384 5834980.1612889 -8081638.2794815
> > 5834913.2788892 -8081533.1785677 5834988.5215889 -8081644.2511244
> >
> 5835062.56996</gml:posList></gml:LinearRing></gml:exterior></gml:Polygon></ogc:Within></ogc:Filter>
> >
> >
> > In Mapserver log, I see
> > FLTLayerApplyPlainFilterToLayer(): ([shape] within fromText('POLYGON
> > ((-8081644.2511243997141719 5835062.5699599999934435,
> > -8081707.5505384001880884 5834980.1612889003008604,
> > -8081638.2794815003871918 5834913.2788891997188330,
> > -8081533.1785677000880241 5834988.5215889001265168,
> > -8081644.2511243997141719 5835062.5699599999934435))'))
> >
> > Then a few lines later, I see that it is not sending the polygon
> > received as filter
> > select ....... where geom_p && ST_GeomFromText('POLYGON((-9239517
> > 5465442,-9239517 9349764,-5565974 9349764,-5565974 5465442,-9239517
> > 5465442))',3857);
> >
> > See the polygon definition is different, postgis receive the extent
> > defined in the mapfile
> > EXTENT -9239517 5465442 -5565974 9349764
> >
> >
> > And, in postgis log I see this query, See the
> > select ....... where geom_p && ST_GeomFromText('POLYGON((-9239517
> > 5465442,-9239517 9349764,-5565974 9349764,-5565974 5465442,-9239517
> > 5465442))',3857);
> >
> >
> > Why Mapserver is not sending the polygon received as filter to postgis?
> >
> >
> > Thanks!
> >
> > /Steve Toutant, M. Sc./
> > Analyste en géomatique
> > Secteur environnement
> > Direction de la santé environnementale et de la toxicologie
> > Institut national de santé publique du Québec
> > Tél.: 418 646-6777 poste 30015
> > Téléc.: 418 644-4593_
> > __steve.toutant at inspq.qc.ca_ <mailto:steve.toutant at inspq.qc.ca>_
> > __http://www.inspq.qc.ca_ <http://www.inspq.qc.ca/>_
> > __http://www.monclimatmasante.qc.ca_ <http://www.monclimatmasante.qc.ca/>
> >
> > /Pour me rejoindre par courrier/
> > Service de l'infrastructure et du réseau
> > Direction des technologies de l'information
> > Ministère de la Sécurité Publique
> > 2525 boul. Laurier, 2e étage
> > Tour Laurentides
> > Québec, G1V 2L2
> >
> >
> >
> >
> >
> > _______________________________________________
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> > mapserver-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapserver-users
> >
>
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