Indeed, you have heard correct. The idea of sandwiching any piece of artwork between two pieces of glass is never a good idea, as it can encourage moisture to be drawn into the artwork itself.

Floating the map with a selection of textural materials: fabric and/or paper mats would possibly work. You have not identified where you are located, but if you email me directly, I'd be glad to recommend a framer near you who might help.

Visiting a local PPFA framer is a good place to start. Simply click on the Find a Framer link in the middle of the PPFA page.

Regards