custom map layer in the map field

Hello

Is there a way to display the map field with a custom layer ?
I would like to add a geological map or layer instead the roadmap or satellite map, for example with openlayer

The source's map are here :
infoterre.brgm.fr/page/geoservices-ogc

Thanks.

Hello

I have search for the documentation of google maps,
and i see that google map supports custom overlays

developers.google.com/maps/documentation...cript/customoverlays
webdesign.tutsplus.com/tutorials/the-goo...ays--webdesign-13868

we do not have support for it
and i have little idea of how much work would be to get it to work smoothly

Hello Ggppdk

thank you for your reply. As I'm not good enough in english to understand your last sentence (some hidden meaning ?) can you clarify it for me ?
Does it mean that there is a lot of work and you're not going to do it, or does it mean that it will take some time, but maybe in a future release ?

I'm currently using the openstreetmaps. I've seen that you use leafletjs.com/ to render the map (but I don't know the way you use it).
I was thinking that, as you can add wms layers ( leafletjs.com/reference-1.6.0.html#tilelayer-wms ), maybe there would be a easy method to add this code ?

Anyway, thank you for the answers and have a good Christmas day !