[MapServer-users] WMS with a GPKG-based layer : different responses, dependending on version (1.1.1 vs 1.3.0)

Thu Feb 19 07:26:09 PST 2026

Hi Jukka,

Your suggestions are a good start.

QGIS does not display the same image, depending on the WMS version?
With debug logs, I noticed that mapserver is "calling" mapcache and the
underlying GPKG layer with different zoom values

   - V1.1.1 : zoom = 9

    /layers/baselayers/wms?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&BBOX=20.01075873940679628%2C37.79416048728808875%2C21.97950873940680339%2C39.03297139830504392&SRS=EPSG%3A4326&WIDTH=1416&HEIGHT=891&LAYERS=osm_4326&STYLES=&FORMAT=image%2Fpng&DPI=144&MAP_RESOLUTION=144&FORMAT_OPTIONS=dpi%3A144&TRANSPARENT=TRUE
   /layers/baselayers/wmts/1.0.0/osm_4326/default/WGS84/9/147/568.png
   - V1.3.0 : zoom = 10

    /layers/baselayers/wms?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=37.79416048728808875%2C20.01075873940679628%2C39.03297139830504392%2C21.97950873940680339&CRS=EPSG%3A4326&WIDTH=1416&HEIGHT=891&LAYERS=osm_4326&STYLES=&FORMAT=image%2Fpng&DPI=144&MAP_RESOLUTION=144&FORMAT_OPTIONS=dpi%3A144&TRANSPARENT=TRUE
   /layers/baselayers/wmts/1.0.0/osm_4326/default/WGS84/10/296/1149.png

It is just as if mapserver is not computing the resolution the same way,
depending on the WMS version.

I modified the V1.1.1 request with :

   - CRS=CRS:84 (instead of EPSG:4326)
   - VERSION=1.3.0 (on coordinate inversion with this code)

With these modifications, the response is identical to V1.1.1

Conclusion ?
There might be some resolution  computation error (or approximation) when
axis orders are swapped.

Thanks again for your help
Philippe

On Thu, Feb 19, 2026 at 1:08 PM Rahkonen Jukka <
jukka.rahkonen at maanmittauslaitos.fi> wrote:

> Hi,
>
> Without a mapfile and data and configurations which could be used for
> re-producing your issue it is hard to guess what happens. Some suggestions:
>
> Make two QGIS WMS connections to your MapServer, one for both versions. If
> the result is good, then Mapserver is good. If the result is bad, you can
> capture the GetMap requests from the QGIS log window.
> If Mapserver is good but Mapserver+Mapcache not, log the GetMap requests
> that Mapcache is sending.
>
> The vendor option "map_resolution"
> https://mapserver.org/ogc/wms_server.html#vendor-specific-wms-parameters
> does have on effect on the size of the labels, but it is not used in your
> example GetMaps.
>
> -Jukka Rahkonen-
>
> ________________________________________
> Lähettäjä: MapServer-users <mapserver-users-bounces at lists.osgeo.org>
> käyttäjän Philippe Ghesquiere via MapServer-users <
> mapserver-users at lists.osgeo.org> puolesta
> Lähetetty: Torstai 19. helmikuuta 2026 11.33
> Vastaanottaja: TC Haddad <tchaddad at gmail.com>
> Kopio: mapserver-users at lists.osgeo.org <mapserver-users at lists.osgeo.org>
> Aihe: Re: [MapServer-users] WMS with a GPKG-based layer : different
> responses, dependending on version (1.1.1 vs 1.3.0)
>
> Hi Tanya,I wouldn't say Mapserver has limited support for WMS V1.3.0. I
> would rather bet for some parameters I have not set.PhilippeP.S. : you
> should answer to "all" so that the whole list can benefit from the
> discussion, and the possible solution.On Thu, Feb 19, 2026 at 9:45 AM TC
> Haddad <tchaddad at gmail.com> wrote:Understood and makes sense.I note that
> the MapCache documentation says there is limited support for WMS 1.3.0, so
> perhaps you should try sending the 1.3.0 request directly to MapServer as a
> test to confirm that the problem is coming from MapCache…TanyaOn Thu, Feb
> 19, 2026 at 12:41 AM Philippe Ghesquiere <philippe.ghesquiere at airbus.com>
> wrote:Dear Tanya,I agree with you. I have no problems with WMTS requests,
> since they explicitly specify the expected zoom level.However, our server
> has to expose WMS services, and I do not know which WMS version our
> potential clients will request.Thus, our server parameters need to be
> adapted in order to serve images with correct content, whatever the
> version.SincerelyPhilippeOn Thu, Feb 19, 2026 at 9:11 AM TC Haddad <
> tchaddad at gmail.com> wrote:Hi Philippe,Apologies if I misunderstood, but
> If your GPKG contains tiles and you are using Mapcache, then you could try
> using WMTS to request the tiles. That way you should get them as rendered
> (instead of re-rendered for single-image returned from WMS).TanyaOn Wed,
> Feb 18, 2026 at 11:48 PM Philippe Ghesquiere via MapServer-users <
> mapserver-users at lists.osgeo.org> wrote:Hi Jukka,The  https://pasteboard.co server
> was down yesterday. It's up again this morning :-)You can see the "WMS
> V1.3.0" is not readable.I also noticed there was no problem with
> demo.mapserver.org WMS examples. I believe these links are "vector
> based", just like this one :
> https://demo.mapserver.org/cgi-bin/umn?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=44.97440639080338087,-93.19614722958594655,44.9933979530691488,-93.16564743649665559&CRS=EPSG:4326&WIDTH=1023&HEIGHT=637&LAYERS=osm-mn&STYLES=&FORMAT=image/png&DPI=96&MAP_RESOLUTION=96&FORMAT_OPTIONS=dpi:96&TRANSPARENT=TRUEI
> really wonder what parameters (or lack of) may change responses between WMS
> responses.SincerelyPhilippeOn Wed, Feb 18, 2026 at 2:30 PM Rahkonen Jukka <
> jukka.rahkonen at maanmittauslaitos.fi> wrote:Hi,I could not access your
> sample images. I do not know if demo.mapserver.org is GPKG based, but I
> do not see any difference between these two outputs:
> https://demo.mapserver.org/cgi-bin/wms?SERVICE=WMS&VERSION=1.1.0&REQUEST=GetMap&BBOX=4.735,33.118,8.641,38.769&SRS=EPSG%3A4326&WIDTH=490&HEIGHT=709&LAYERS=cities&STYLES=&FORMAT=image%2Fpng&DPI=144&MAP_RESOLUTION=144&FORMAT_OPTIONS=dpi%3A144&TRANSPARENT=TRUEhttps://demo.mapserver.org/cgi-bin/wms?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=33.118,4.735,38.769,8.641&CRS=EPSG%3A4326&WIDTH=490&HEIGHT=709&LAYERS=cities&STYLES=&FORMAT=image%2Fpng&DPI=144&MAP_RESOLUTION=144&FORMAT_OPTIONS=dpi%3A144&TRANSPARENT=TRUE-Jukka
> Rahkonen-________________________________________Lähettäjä: MapServer-users
> <mapserver-users-bounces at lists.osgeo.org> käyttäjän Philippe Ghesquiere
> via MapServer-users <mapserver-users at lists.osgeo.org> puolestaLähetetty:
> Keskiviikko 18. helmikuuta 2026 11.37Vastaanottaja: MapServer Users <
> mapserver-users at lists.osgeo.org>Aihe: [MapServer-users] WMS with a
> GPKG-based layer : different responses, dependending on version (1.1.1 vs
> 1.3.0)Hi all,1) Problem description:Our system is offering an OSM layer,
> based on a WGS84 GPKG (Z=0 to Z=13).I sent two WMS requests, where the only
> difference is the standard version :WMS V1.1.1 request:
> https://xxx/layers/baselayers/wms?service=WMS&version=1.1.1&request=GetMap&Layers=osm_4326&Styles=&SRS=EPSG:4326&Format=image/png&BBOX=45,22.5,67.5,45&Width=1024&Height=1024WMS
> V1.3.0 request:
> https://xxx/layers/baselayers/wms?service=WMS&version=1.3.0&request=GetMap&Layers=osm_4326&Styles=&CRS=EPSG:4326&Format=image/png&BBOX=22.5,45,45,67.5&Width=1024&Height=1024
> I observe some differences :V1.1.1:
> https://pasteboard.co/JjKbU4yvSxrM.png,Labels are easy to read:
> mapcache/mapserver is selecting the right zoom level in the GPKG
> file.V1.3.0: https://pasteboard.co/XzpHSJjSTiQV.png.Labels are much too
> small and not readable. It seems that mapcache/mapserver is selecting a
> higher zoom level than expected and down-sample the image.I do not
> understand why the rendering is not the same.As far as I know, WMS
> requests do not have standard parameters which give a *direct* access to
> zoom layer, resolution or DPI.I tried to add some parameters to my request,
> with no impact on the
> response: DPI=240MAP_RESOLUTION=240FORMAT_OPTIONS=dpi:240.I also tried to
> add parameters in the "MAP block":RESOLUTIONDEFRESOLUTION2) Software
> environment:Mapserver 8.2.0Mapcache 1.14.0Gdal V3.8.4Alma Linux V83) Map
> file excerptMAP    NAME "baselayers_wms"    STATUS ON    SIZE 256 256
> EXTENT -180.0 -90.0 180.0 90.0    UNITS dd#    DEFRESOLUTION 200#
>  RESOLUTION  144    PROJECTION        "init=epsg:4326"    END4) My
> questions:Why do I get different responses between V1.1.1 and V1.3.0 WMS
> requests ?Are there any configuration parameters which have default values
> in one version and not in the other ?I would be glad to have some hints to
> get better WMS 1.3.0 responsesSincerelyPhilippeThe information in this
> e-mail is confidential. The contents may not be disclosed or used by anyone
> other than the addressee. Access to this e-mail by anyone else is
> unauthorised.If you are not the intended recipient, please notify Airbus
> immediately and delete this e-mail.Airbus cannot accept any responsibility
> for the accuracy or completeness of this e-mail as it has been sent over
> public networks. If you have any concerns over the content of this message
> or its Accuracy or Integrity, please contact Airbus immediately.All
> outgoing e-mails from Airbus are checked using regularly updated virus
> scanning software but you should take whatever measures you deem to be
> appropriate to ensure that this message and any attachments are virus
> free.The information in this e-mail is confidential. The contents may not
> be disclosed or used by anyone other than the addressee. Access to this
> e-mail by anyone else is unauthorised.If you are not the intended
> recipient, please notify Airbus immediately and delete this e-mail.Airbus
> cannot accept any responsibility for the accuracy or completeness of this
> e-mail as it has been sent over public networks. If you have any concerns
> over the content of this message or its Accuracy or Integrity, please
> contact Airbus immediately.All outgoing e-mails from Airbus are checked
> using regularly updated virus scanning software but you should take
> whatever measures you deem to be appropriate to ensure that this message
> and any attachments are virus
> free._______________________________________________MapServer-users mailing
> listMapServer-users at lists.osgeo.orghttps://
> lists.osgeo.org/mailman/listinfo/mapserver-usersThe information in this
> e-mail is confidential. The contents may not be disclosed or used by anyone
> other than the addressee. Access to this e-mail by anyone else is
> unauthorised.If you are not the intended recipient, please notify Airbus
> immediately and delete this e-mail.Airbus cannot accept any responsibility
> for the accuracy or completeness of this e-mail as it has been sent over
> public networks. If you have any concerns over the content of this message
> or its Accuracy or Integrity, please contact Airbus immediately.All
> outgoing e-mails from Airbus are checked using regularly updated virus
> scanning software but you should take whatever measures you deem to be
> appropriate to ensure that this message and any attachments are virus
> free.The information in this e-mail is confidential. The contents may not
> be disclosed or used by anyone other than the addressee. Access to this
> e-mail by anyone else is unauthorised.If you are not the intended
> recipient, please notify Airbus immediately and delete this e-mail.Airbus
> cannot accept any responsibility for the accuracy or completeness of this
> e-mail as it has been sent over public networks. If you have any concerns
> over the content of this message or its Accuracy or Integrity, please
> contact Airbus immediately.All outgoing e-mails from Airbus are checked
> using regularly updated virus scanning software but you should take
> whatever measures you deem to be appropriate to ensure that this message
> and any attachments are virus free.
The information in this e-mail is confidential. The contents may not be disclosed or used by anyone other than the addressee. Access to this e-mail by anyone else is unauthorised.
If you are not the intended recipient, please notify Airbus immediately and delete this e-mail.
Airbus cannot accept any responsibility for the accuracy or completeness of this e-mail as it has been sent over public networks. If you have any concerns over the content of this message or its Accuracy or Integrity, please contact Airbus immediately.
All outgoing e-mails from Airbus are checked using regularly updated virus scanning software but you should take whatever measures you deem to be appropriate to ensure that this message and any attachments are virus free.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/mapserver-users/attachments/20260219/d4446c0d/attachment-0001.htm>