[MapServer-users] Changing opacity of one layer in a multilayer WMS request URL with MapServer 8

[Matthew Graber]

Glad I could help, Jeff! MapServer.pdf is a great resource!

-Matt

On Tue, Feb 21, 2023 at 1:02 PM Jeff McKenna <jmckenna at gatewaygeomatics.com>
wrote:

> Wonderful to hear that you are using the MapServer.pdf!  (I actually put
> much effort into maintaining that PDF output, that but I never hear
> feedback...until someone reports a problem, like you did now, ha).
> Sometimes my updates differ from website rebuilds, will be sure to
> update the PDF for the upcoming 8.0.1 release.
>
> Again, thanks for this report!
>
> (also, don't be afraid to report doc issues like this at
> https://github.com/MapServer/MapServer-documentation/issues )
>
> thanks again for the report!
>
> -jeff
>
>
>
>
> --
> Jeff McKenna
> GatewayGeo: Developers of MS4W, MapServer Consulting and Training
> co-founder of FOSS4G
> http://gatewaygeo.com/
>
>
>
> On 2023-02-21 12:52 p.m., Matthew Graber wrote:
> > Hello all!
> >
> > With MapServer 8, I'm wondering what the proper way to change the
> > opacity of a single layer in a multilayer WMS request is.
> >
> > For example, the following URL excerpt shows the old way of
> > accomplishing this that worked while using MapServer 7:
> >
> >
> SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&LAYERS=test_a,test_b&map.layer[test_b]=OPACITY+50
> >
> > My understanding is that this would have the same effect as adding
> > "OPACITY 50" to the test_b layer in the mapfile. The mapfile containing
> > test_a and test_b did not have OPACITY included when they were written.
> > Obviously, this no longer works with MapServer 8, and now that request
> > has the same results as omitting the "&map.layer[test_b]=OPACITY+50"
> > portion entirely.
> >
> > Based on https://mapserver.org/fr/MIGRATION_GUIDE.html
> > <https://mapserver.org/fr/MIGRATION_GUIDE.html>, I see that OPACITY now
> > belongs inside a COMPOSITE object. I tried the following modifications
> > to the request URL:
> >
> >
> SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&LAYERS=test_a,test_b&map.layer[test_b].composite=OPACITY+50
> >
> SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&LAYERS=test_a,test_b&map.layer[test_b].composite[0]=OPACITY+50
> >
> > I also tried this both with the mapfile left as-is, and with an empty
> > COMPOSITE object being included in each layer object, and each time I
> > got the same unsuccessful result as before.
> >
> > Is there a way to accomplish this in MapServer 8?
> >
> > Also, does this map.layer[layername]=... syntax still work in MapServer
> > 8? The documentation at
> > https://mapserver.org/cgi/controls.html#using-mapserver-version-8
> > <https://mapserver.org/cgi/controls.html#using-mapserver-version-8>
> > suggests it might no longer work for MapServer 8 (based on the heading
> > "Using MapServer version < 8"), but the documentation at
> > https://mapserver.org/pdf/MapServer.pdf
> > <https://mapserver.org/pdf/MapServer.pdf> shows the same examples with
> > the heading "Using MapServer version <= 8" on page 1065 of the PDF, so
> > I'm unsure if this is still intended to work in MapServer 8.
> >
> > Thank you,
> > Matt
> >
> > _______________________________________________
> > MapServer-users mailing list
> > MapServer-users at lists.osgeo.org
> > https://lists.osgeo.org/mailman/listinfo/mapserver-users
>
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