So, can I open a feature request? Best, Michal Kowalczuk
W dniu czw., 12.09.2024 o 13:57 Rahkonen Jukka < jukka.rahko...@maanmittauslaitos.fi> napisał(a): > Hi, > > > > Your suggestion to utilize the additional layer BBOXes if they exist feels > good to me, and better than to use the first advertised SRS from the root > level. Beyond that what can be done with parsing the GetCapabilities is > limited in my mind, because all projections which are supported may not be > useful in real life. > > > > -Jukka Rahkonen- > > > > *Lähettäjä:* Michał Kowalczuk <michkowalc...@gmail.com> > *Lähetetty:* torstai 12. syyskuuta 2024 14.35 > > > *Vastaanottaja:* Rahkonen Jukka <jukka.rahko...@maanmittauslaitos.fi> > *Kopio:* gdal-dev@lists.osgeo.org > *Aihe:* Re: [gdal-dev] WMS supported SRS > > > > So we remain at the point that there is no good method that, using only > GDAL, will allow to fully use the WMS service without additional work > related to XML parsing...? > > > > Best, > > Michał Kowalczuk > > > > wt., 10 wrz 2024 o 17:06 Michał Kowalczuk <michkowalc...@gmail.com> > napisał(a): > > A sample from your link: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > *<Layer queryable="1" opaque="0"> <Name>Rakennustietoruudukko_2017</Name> > <Title>Rakennustietoruudukko 2017</Title> <Abstract>Tietoa rakennuksista > 250 x 250m ruudukoissa pääkaupunkiseudulla</Abstract> <KeywordList> > <Keyword>features</Keyword> <Keyword>Rakennustietoruudukko_2017</Keyword> > </KeywordList> <CRS>EPSG:3879</CRS> <CRS>CRS:84</CRS> > <EX_GeographicBoundingBox> > <westBoundLongitude>24.50112802448554</westBoundLongitude> > <eastBoundLongitude>25.25849178466466</eastBoundLongitude> > <southBoundLatitude>60.052265324029165</southBoundLatitude> > <northBoundLatitude>60.39874702231777</northBoundLatitude> > </EX_GeographicBoundingBox> <BoundingBox CRS="CRS:84" > minx="24.50112802448554" miny="60.052265324029165" maxx="25.25849178466466" > maxy="60.39874702231777"/> <BoundingBox CRS="EPSG:3879" minx="6659998.5" > miny="2.5472498E7" maxx="6698499.5" maxy="2.551425E7"/> <Style> > <Name>polygon</Name> <Title>Default polygon style</Title> <Abstract>A > sample style that just draws out a solid gray interior with a black 1px > outline</Abstract> <LegendURL width="20" height="20"> > <Format>image/png</Format> <OnlineResource > xmlns:xlink="http://www.w3.org/1999/xlink <http://www.w3.org/1999/xlink>" > xlink:type="simple" > xlink:href="https://kartta.hsy.fi/geoserver/asuminen_ja_maankaytto/ows?service=WMS&version=1.3.0&request=GetLegendGraphic&format=image%2Fpng&width=20&height=20&layer=Rakennustietoruudukko_2017 > <https://kartta.hsy.fi/geoserver/asuminen_ja_maankaytto/ows?service=WMS&version=1.3.0&request=GetLegendGraphic&format=image%2Fpng&width=20&height=20&layer=Rakennustietoruudukko_2017>"/> > </LegendURL> </Style> </Layer>* > > > > wt., 10 wrz 2024 o 17:05 Michał Kowalczuk <michkowalc...@gmail.com> > napisał(a): > > Ok, now I see the problem. Thank you Jukka for the explanation with a > sample. > > So maybe we can use information from *BoundingBox*? > > and generate SUBDATASETS for each combination of Layer and BoundingBox > definition that is usually defined for "best"/dedicated projections for a > layer. > > > > *(7.2.4.6.8 )* > > *A Layer may have multiple BoundingBox elements, but each one shall state > a different CRS (...)* > > *A Layer shall not provide a BoundingBox for a CRS it does not support. > Conversely, a Layer may support CRSs* > > *for which it does not provide a BoundingBox: a server that has the > ability to transform data to different CRSs may* > > *choose not to provide an explicit BoundingBox for every possible CRS > available for each Layer. The server* > > *should provide BoundingBox information for at least the native CRS of the > Layer (that is, the CRS in which the* > > *Layer is stored in the server’s database).* > > > > Best, > > Michał > > > > W dniu wt., 10.09.2024 o 16:07 Rahkonen Jukka < > jukka.rahko...@maanmittauslaitos.fi> napisał(a): > > Hi > > > > - I meant to use CRSs only reported by GetCapabilities. I haven't seen > that GetCapabilities returns so many (6782) possible projections... > > > > I was meaning the same, CRSs reported in GetCapabilities. I used a search > engine with phrase “service=WMS&version=1.3.0” and found in three minutes > many examples, including this one > kartta.hsy.fi/geoserver/asuminen_ja_maankaytto/ows?service=WMS&version=1.3.0&request=GetCapabilities. > If you want to see more, install Geoserver on your computer and have a look > at the default GetCapabilities. > > > > Finding the best CRS from WMS GetCapabilities is guesswork. The server > above is a Finnish one so probably EPSG:3067 is the most native CRS because > that is what we tend to use in Finland. However, there is also one and only > one additional BBOX for EPSG:3879 in GetCapabilities, but that would be > somewhat odd selection for a country-wide CRS. It is also possible that for > example some CRS of New Zealand does not really work in GetMap of the > Finnish data even GetCapabilities says it will. But when WMS is configured > to show a short CRS list then I would trust that they are all good to use. > Just be aware that the list can also be very long. > > > > If you start implementing the LIST_ALL_SRS option, it should be noted that > the service level CRS list applies to all layers, and each layer can add > more CRSs to the list. Maybe in theory there could be even > “crs-list-of-service-root + crs-list-of-group-layer + > crs-list-of-child-layer”. > > > > “7.2.4.6.7 CRS > > Every Layer is available in one or more layer coordinate reference > systems. 6.7.3 discusses the Layer CRS. In > > order to indicate which Layer CRSs are available, every named Layer shall > have at least one <CRS> element that > > is either stated explicitly or inherited from a parent Layer. The root > <Layer> element shall include a sequence of > > zero or more CRS elements listing all CRSs that are common to all > subsidiary layers. A child layer may optionally > > add to the list inherited from a parent layer. Any duplication shall be > ignored by clients. > > When a Layer is available in several coordinate reference systems, the > list of available CRS values shall be > > represented as a sequence of <CRS> elements, each of which contains only a > single CRS name.” > > > > -Jukka Rahkonen- > > > > > > > > > > *Lähettäjä:* Michał Kowalczuk <michkowalc...@gmail.com> > *Lähetetty:* tiistai 10. syyskuuta 2024 16.32 > *Vastaanottaja:* Rahkonen Jukka <jukka.rahko...@maanmittauslaitos.fi> > *Kopio:* gdal-dev@lists.osgeo.org > > > *Aihe:* Re: [gdal-dev] WMS supported SRS > > > > Thank you for your feedback. My comments are below: > > > > *It means that there are tens of thousands WMS services which support 6782 > different projections for each layer (checked from Geoserver version > 2.25.3). I would not like them all to be reported as subdatasets.* > > I meant to use CRSs only reported by GetCapabilities. I haven't seen that > GetCapabilities returns so many (6782) possible projections... > > > > *WMS standard also does not define any default CRS and the first one on > the list in GetCapabilities does not need to be the best.* > > Therefore, the current form of the generating subdatasets names method for > WMS driver is even more useless, if we have a non-default (not the best) > projection for the data. > > > > And the only good way to work with it is to parse XML and generate paths > manually... > > > > That's why I favor Even's option to introduce open option > LIST_ALL_SRS=YES/NO. > > > > Any more thoughts? > > > > Michał Kowalczuk > > > > wt., 10 wrz 2024 o 15:03 Rahkonen Jukka < > jukka.rahko...@maanmittauslaitos.fi> napisał(a): > > Hi, > > > > WMTS typically supports a rather small number of tilematrices and tiles > are usually cached, so it makes a lot of sense to advertise the available > matrices and utilize them. On the other hand WMS maps are created > on-the-fly and there is very low technical cost on the server side to > support however many projections. WMS standard also does not define any > default CRS and the first one on the list in GetCapabilities does not need > to be the best. > > > > I guess that Geoserver is the most common WMS server in the world and > amazingly many Geoservers run with the default settings. It means that > there are tens of thousands WMS services which support 6782 different > projections for each layer (checked from Geoserver version 2.25.3). I would > not like them all to be reported as subdatasets. > > > > I can see that ogrinfo and the OGC API Features driver report the list of > supported projections. Test with ogrinfo OAPIF: > https://ogc-api.nrw.de/inspire-us-feuerwehr -al -so shows “Supported SRS: > OGC:CRS84, EPSG:25832, EPSG:25833, EPSG:4258, EPSG:4326, EPSG:3395, > EPSG:3857, EPSG:3034, EPSG:3035” > > Something similar might be an option for gdalinfo, but still about 6782 > EPSG codes per layer is too much to be viewed by default. Maybe the CRS > list could be reported under some metadata domain that user could read on > demand? > > > > -Jukka Rahkonen- > > > > > > > > > > > > > > > > > > > > *Lähettäjä:* gdal-dev <gdal-dev-boun...@lists.osgeo.org> *Puolesta *Michal > Kowalczuk via gdal-dev > *Lähetetty:* tiistai 10. syyskuuta 2024 15.15 > *Vastaanottaja:* gdal-dev@lists.osgeo.org > *Aihe:* Re: [gdal-dev] WMS supported SRS > > > > I found that there was a similar issue in 2021 without any specific answer: > > https://www.mail-archive.com/gdal-dev@lists.osgeo.org/msg35549.html > > > > I wonder if getting SUBDATASETS shouldn't return the result in a similar > way as it does for WMTS service, > > where GDAL generates paths to all layer/tilematrix/tilematrixset > combination. > > For example if layer is available in 3 SRS, GDAL produces 3 subdatasets, > so using only SUBDATASE_NAME property user has access to all map services > shared by WMTS server. > > In my opinion, GDAL should use the same approach for WMS. > > > > Does anyone object? > > I will then submit a new feature request/bug report. > > > > Best regards and have a nice day > > Michał Kowalczuk > > > > pon., 9 wrz 2024 o 16:17 Michał Kowalczuk <michkowalc...@gmail.com> > napisał(a): > > Hi, > > Does GDAL provides a method to get supported spatial reference systems by > WMS service? > > *GDALGetMetadata(SUBDATASETS) *generate links only for the first > (default) SRS from GetCapabilities, so this won't be helpful. > > Working with WFS I can get supported SRS using OGR > *OGR_L_GetSupportedSRSList *function. > > Does GDAL offers something similar for WMS, or should I get this > information from GetCapabilities XML by myself? > > > > Regards, > > Michal > >
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