[QGIS-Developer] QGIS-Server: filter by categories in an OGC compatible way

Tue Apr 9 07:47:48 PDT 2019

Hi Andreas,
no, I'm afraid not, the WMS specification provided no way to filter, and
even the SLD/SLD_BODY parameters are not part of the WMS specification,
but part of the SLD one, which a server might decide to implement, or not

Cheers
Andrea

On Tue, Apr 9, 2019 at 4:46 PM Andreas Neumann <a.neumann at carto.net> wrote:

> Hi Andrea,
>
> Ah - thanks a lot! This helps.
>
> Is there also a simpler OGC compatible way available to filter away
> categories in a layer if there is no intent to re-style the categories in a
> layer?
>
> Thanks,
>
> Andreas
>
> On 2019-04-09 16:18, Andrea Aime wrote:
>
> Hi,
> if you want to pass a verbatim SLD, you should use SLD_BODY. This seems to
> work:
>
>
> https://services.geo.zg.ch/ows-oereb/Grundwasserschutz?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=2682932,1225299,2684213,1226054&CRS=EPSG:2056&WIDTH=1615&HEIGHT=952&LAYERS=ch.zg.grundwasserschutz.gwszonen&STYLES=&FORMAT=image/png&DPI=96&MAP_RESOLUTION=96&FORMAT_OPTIONS=dpi:96&TRANSPARENT=TRUE&SLD_BODY=%3CStyledLayerDescriptor+xmlns%3D%22http%3A%2F%2Fwww.opengis.net%2Fsld%22+xmlns%3Axlink%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxlink%22+xmlns%3Axsi%3D%22http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema-instance%22+xsi%3AschemaLocation%3D%22http%3A%2F%2Fwww.opengis.net%2Fsld+http%3A%2F%2Fschemas.opengis.net%2Fsld%2F1.1.0%2FStyledLayerDescriptor.xsd%22+xmlns%3Ase%3D%22http%3A%2F%2Fwww.opengis.net%2Fse%22+version%3D%221.1.0%22+xmlns%3Aogc%3D%22http%3A%2F%2Fwww.opengis.net%2Fogc%22%3E%0D%0A+%3CNamedLayer%3E%0D%0A++%3Cse%3AName%3Ech.zg.grundwasserschutz.gwszonen%3C%2Fse%3AName%3E%0D%0A++%3CUserStyle%3E%0D%0A+++%3Cse%3AName%3Edefault%3C%2Fse%3AName%3E%0D%0A+++%3Cse%3AFeatureTypeStyle%3E%0D%0A++++%3Cse%3ARule%3E%0D%0A+++++%3Cse%3AName%3EGrundwasserschutzzone+S1%3C%2Fse%3AName%3E%0D%0A+++++%3Cse%3ADescription%3E%0D%0A++++++%3Cse%3ATitle%3EGrundwasserschutzzone+S1%3C%2Fse%3ATitle%3E%0D%0A+++++%3C%2Fse%3ADescription%3E%0D%0A+++++%3Cogc%3AFilter+xmlns%3Aogc%3D%22http%3A%2F%2Fwww.opengis.net%2Fogc%22%3E%0D%0A++++++%3Cogc%3APropertyIsEqualTo%3E%0D%0A+++++++%3Cogc%3APropertyName%3Etyp_code%3C%2Fogc%3APropertyName%3E%0D%0A+++++++%3Cogc%3ALiteral%3ES1%3C%2Fogc%3ALiteral%3E%0D%0A++++++%3C%2Fogc%3APropertyIsEqualTo%3E%0D%0A+++++%3C%2Fogc%3AFilter%3E%0D%0A+++++%3Cse%3APolygonSymbolizer%3E%0D%0A++++++%3Cse%3AFill%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22fill%22%3E%23003bb3%3C%2Fse%3ASvgParameter%3E%0D%0A++++++%3C%2Fse%3AFill%3E%0D%0A++++++%3Cse%3AStroke%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22stroke%22%3E%23000080%3C%2Fse%3ASvgParameter%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22stroke-width%22%3E1%3C%2Fse%3ASvgParameter%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22stroke-linejoin%22%3Ebevel%3C%2Fse%3ASvgParameter%3E%0D%0A++++++%3C%2Fse%3AStroke%3E%0D%0A+++++%3C%2Fse%3APolygonSymbolizer%3E%0D%0A++++%3C%2Fse%3ARule%3E%0D%0A+++%3C%2Fse%3AFeatureTypeStyle%3E%0D%0A++%3C%2FUserStyle%3E%0D%0A+%3C%2FNamedLayer%3E%0D%0A%3C%2FStyledLayerDescriptor%3E
>
> Using &sld=... you should feed it with a URL that the SLD can be
> downloaded from instead
> (none of this is QGIS specific, it's just how the SLD specification says
> user provided styles should be used).
>
> Cheers
> Andrea
>
> On Tue, Apr 9, 2019 at 4:15 PM Andreas Neumann <a.neumann at carto.net>
> wrote:
>
>> Hi,
>>
>> I did some test:
>>
>> Here is a long URL with the SLD (originally sent by QGIS server, stripped
>> away some RULES manually) and sending it back in a GetMap request:
>>
>>
>> https://services.geo.zg.ch/ows-oereb/Grundwasserschutz?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=2682932,1225299,2684213,1226054&CRS=EPSG:2056&WIDTH=1615&HEIGHT=952&LAYERS=ch.zg.grundwasserschutz.gwszonen&STYLES=&FORMAT=image/png&DPI=96&MAP_RESOLUTION=96&FORMAT_OPTIONS=dpi:96&TRANSPARENT=TRUE&SLD=%3CStyledLayerDescriptor+xmlns%3D%22http%3A%2F%2Fwww.opengis.net%2Fsld%22+xmlns%3Axlink%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxlink%22+xmlns%3Axsi%3D%22http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema-instance%22+xsi%3AschemaLocation%3D%22http%3A%2F%2Fwww.opengis.net%2Fsld+http%3A%2F%2Fschemas.opengis.net%2Fsld%2F1.1.0%2FStyledLayerDescriptor.xsd%22+xmlns%3Ase%3D%22http%3A%2F%2Fwww.opengis.net%2Fse%22+version%3D%221.1.0%22+xmlns%3Aogc%3D%22http%3A%2F%2Fwww.opengis.net%2Fogc%22%3E%0D%0A+%3CNamedLayer%3E%0D%0A++%3Cse%3AName%3Ech.zg.grundwasserschutz.gwszonen%3C%2Fse%3AName%3E%0D%0A++%3CUserStyle%3E%0D%0A+++%3Cse%3AName%3Edefault%3C%2Fse%3AName%3E%0D%0A+++%3Cse%3AFeatureTypeStyle%3E%0D%0A++++%3Cse%3ARule%3E%0D%0A+++++%3Cse%3AName%3EGrundwasserschutzzone+S1%3C%2Fse%3AName%3E%0D%0A+++++%3Cse%3ADescription%3E%0D%0A++++++%3Cse%3ATitle%3EGrundwasserschutzzone+S1%3C%2Fse%3ATitle%3E%0D%0A+++++%3C%2Fse%3ADescription%3E%0D%0A+++++%3Cogc%3AFilter+xmlns%3Aogc%3D%22http%3A%2F%2Fwww.opengis.net%2Fogc%22%3E%0D%0A++++++%3Cogc%3APropertyIsEqualTo%3E%0D%0A+++++++%3Cogc%3APropertyName%3Etyp_code%3C%2Fogc%3APropertyName%3E%0D%0A+++++++%3Cogc%3ALiteral%3ES1%3C%2Fogc%3ALiteral%3E%0D%0A++++++%3C%2Fogc%3APropertyIsEqualTo%3E%0D%0A+++++%3C%2Fogc%3AFilter%3E%0D%0A+++++%3Cse%3APolygonSymbolizer%3E%0D%0A++++++%3Cse%3AFill%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22fill%22%3E%23003bb3%3C%2Fse%3ASvgParameter%3E%0D%0A++++++%3C%2Fse%3AFill%3E%0D%0A++++++%3Cse%3AStroke%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22stroke%22%3E%23000080%3C%2Fse%3ASvgParameter%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22stroke-width%22%3E1%3C%2Fse%3ASvgParameter%3E%0D%0A+++++++%3Cse%3ASvgParameter+name%3D%22stroke-linejoin%22%3Ebevel%3C%2Fse%3ASvgParameter%3E%0D%0A++++++%3C%2Fse%3AStroke%3E%0D%0A+++++%3C%2Fse%3APolygonSymbolizer%3E%0D%0A++++%3C%2Fse%3ARule%3E%0D%0A+++%3C%2Fse%3AFeatureTypeStyle%3E%0D%0A++%3C%2FUserStyle%3E%0D%0A+%3C%2FNamedLayer%3E%0D%0A%3C%2FStyledLayerDescriptor%3E
>>
>> The response is:
>> <ServiceExceptionReport xmlns="http://www.opengis.net/ogc" version="1.3.0
>> ">
>> <ServiceException code="Invalid Parameter">
>> SLD ('<StyledLayerDescriptor xmlns="http://www.opengis.net/sld"
>> xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="
>> http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="
>> http://www.opengis.net/sld
>> http://schemas.opengis.net/sld/1.1.0/StyledLayerDescriptor.xsd"
>> xmlns:se="http://www.opengis.net/se" version="1.1.0" xmlns:ogc="
>> http://www.opengis.net/ogc"> <NamedLayer>
>> <se:Name>ch.zg.grundwasserschutz.gwszonen</se:Name> <UserStyle>
>> <se:Name>default</se:Name> <se:FeatureTypeStyle> <se:Rule>
>> <se:Name>Grundwasserschutzzone S1</se:Name> <se:Description>
>> <se:Title>Grundwasserschutzzone S1</se:Title> </se:Description> <ogc:Filter
>> xmlns:ogc="http://www.opengis.net/ogc"> <ogc:PropertyIsEqualTo>
>> <ogc:PropertyName>typ_code</ogc:PropertyName> <ogc:Literal>S1</ogc:Literal>
>> </ogc:PropertyIsEqualTo> </ogc:Filter> <se:PolygonSymbolizer> <se:Fill>
>> <se:SvgParameter name="fill">#003bb3</se:SvgParameter> </se:Fill>
>> <se:Stroke> <se:SvgParameter name="stroke">#000080</se:SvgParameter>
>> <se:SvgParameter name="stroke-width">1</se:SvgParameter> <se:SvgParameter
>> name="stroke-linejoin">bevel</se:SvgParameter> </se:Stroke>
>> </se:PolygonSymbolizer> </se:Rule> </se:FeatureTypeStyle> </UserStyle>
>> </NamedLayer> </StyledLayerDescriptor>') cannot be converted into QString
>> </ServiceException>
>> </ServiceExceptionReport>
>>
>> So apparently the SLD cannot be converted to a QString. Is my encoding in
>> the URL above wrong or am I missing a required additional parameter?
>>
>> Can you point me to an example how to create a valid GetMap request with
>> an SLD submitted?
>>
>> Thanks a lot,
>> Andreas
>>
>> On 2019-04-09 15:38, Andreas Neumann wrote:
>>
>> Hi,
>>
>> Does QGIS-Server support SLD styles to filter away RULEs in a GetMap
>> Request?
>>
>> I would assume, yes, but in what encoding would I submit such an SLD in a
>> GET request? I know that one should rather use POST reqests for such long
>> parameters, but for experimenting, it would be ok to use GET.
>>
>> The idea would be to allow users to enable/disable categories within a
>> given layer.
>>
>> The WMS client would first request the available rules with a GetStyles
>> command (that part works fine) and would then filter the RULE (strip away
>> the unwanted RULEs) and resubmit the GetMap with an SLD. Does that work
>> with QGIS server?
>>
>> I know that one can also use the FILTER parameter, but we want to do it
>> in an OGC compatible way, since the client being developed should work with
>> any OGC compatible WMS server.
>>
>> Thanks for your reply,
>>
>> Andreas
>>
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>
>
> --
>
> Regards, Andrea Aime == GeoServer Professional Services from the experts!
> Visit http://goo.gl/it488V for more information. == Ing. Andrea Aime
> @geowolf Technical Lead GeoSolutions S.A.S. Via di Montramito 3/A 55054
> Massarosa (LU) phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 339
> 8844549 http://www.geo-solutions.it http://twitter.com/geosolutions_it
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-- 

Regards, Andrea Aime == GeoServer Professional Services from the experts!
Visit http://goo.gl/it488V for more information. == Ing. Andrea Aime
@geowolf Technical Lead GeoSolutions S.A.S. Via di Montramito 3/A 55054
Massarosa (LU) phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 339
8844549 http://www.geo-solutions.it http://twitter.com/geosolutions_it
------------------------------------------------------- *Con riferimento
alla normativa sul trattamento dei dati personali (Reg. UE 2016/679 -
Regolamento generale sulla protezione dei dati “GDPR”), si precisa che ogni
circostanza inerente alla presente email (il suo contenuto, gli eventuali
allegati, etc.) è un dato la cui conoscenza è riservata al/i solo/i
destinatario/i indicati dallo scrivente. Se il messaggio Le è giunto per
errore, è tenuta/o a cancellarlo, ogni altra operazione è illecita. Le
sarei comunque grato se potesse darmene notizia. This email is intended
only for the person or entity to which it is addressed and may contain
information that is privileged, confidential or otherwise protected from
disclosure. We remind that - as provided by European Regulation 2016/679
“GDPR” - copying, dissemination or use of this e-mail or the information
herein by anyone other than the intended recipient is prohibited. If you
have received this email by mistake, please notify us immediately by
telephone or e-mail.*
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