wms legend from mapserver not available in 3d mode because of wrong empty scale parameter

[tdipisa]

Description

loading a layer coming from mapserver, in 2d mode this request is made and show a proper image
https://wms.dev.craig.fr/ign?service=WMS&request=GetLegendGraphic&format=image%2Fpng&height=12&width=12&layer=bdforet_v2&style=&version=1.3.0&SLD_VERSION=1.1.0&LEGEND_OPTIONS=forceLabels%3Aon&SCALE=18056

in 3d mode, this request is made:

https://wms.dev.craig.fr/ign?service=WMS&request=GetLegendGraphic&format=image/png&height=12&width=12&layer=bdforet_v2&style=&version=1.3.0&SLD_VERSION=1.1.0&LEGEND_OPTIONS=forceLabels:on&SCALE=

and the server replies with an XML exception with msCalculateScale(): General error message. Invalid image extent, minx=-0.000000, miny=-0.000000, maxx=0.000000, maxy=0.000000., imo because mapstore sends an empty SCALE parameter.

can reproduce at will with this url which is freely available (wms.dev isnt, and ign service is password-protected):

https://wms.craig.fr/ortho?service=WMS&request=GetLegendGraphic&format=image/png&height=12&width=12&layer=dallage-auvergne-2009&style=&version=1.3.0&SLD_VERSION=1.1.0&LEGEND_OPTIONS=forceLabels:on&SCALE=18056 -> if one removes 18056 then the server barfs.

What kind of improvement you want to add? (check one with "x", remove the others)

• Minor changes to existing features
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

Other useful information

Issue coming from georchestra/mapstore2-georchestra#444

[landryb]

i've locally tested #9024 by checking out allyoucanmap/issue_9006 and my initial issue (reported in georchestra/mapstore2-georchestra#444) is indeed gone:

• in 2d mode, load bdforet_v2 from https://wms.craig.fr/ign
• recenter/zoom on mauzun (instead of having the full extent which is slower)
• switch to 3d mode
• in the TOC, open the layer legend -> it is requested to the server with the right scale parameter (https://wms.craig.fr/ign?service=WMS&request=GetLegendGraphic&format=image/png&height=12&width=12&layer=bdforet_v2&style=&version=1.3.0&SLD_VERSION=1.1.0&LEGEND_OPTIONS=forceLabels:on&SCALE=18056)