[gdal-dev] WMS supported SRS

[Michał Kowalczuk]

That's why I favor Even's option to introduce open option
LIST_ALL_SRS=YES/NO.


Or any other solution that simplify the process of choosing layer in the
specified SRS, e.g. dedicated function that returns list of supported SRS
like in WFS...?


wt., 10 wrz 2024 o 15:31 Michał Kowalczuk <michkowalczuk at gmail.com>
napisał(a):

> 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.rahkonen at 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-bounces at lists.osgeo.org> *Puolesta *Michal
>> Kowalczuk via gdal-dev
>> *Lähetetty:* tiistai 10. syyskuuta 2024 15.15
>> *Vastaanottaja:* gdal-dev at 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 <michkowalczuk at 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
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240910/dd8f0666/attachment-0001.htm>