GTM is built for Joomla's plugin framework, which is a completely
different environment than phpBB.
I'm quite familiar with phpBB (phpBB3 that is) and the way to
build Extensions is far less advanced than Joomla's framework.
In phpBB3, i doubt whether it's possible at all to get something
like GTM to work without changing the Core source codes...
...so i'm afraid the short answer is: No, GTM only works inside Joomla.
I've been using GPXTrackMap on my Joomla website for some time now. I find it very useful. It displays the tracks in quite a nice way and I like it a lot.
I'd like to extend this feature to make it usable for all the site users, not only the editors.
At the moment I think the GPXTrackMap is only available for a Joomla user that can upload his GPX files to the server and is allowed to post a Joomla article. However, there are only a handful of users that have those rights. Most of the users are just registered users without such rights. All users have access to the sites phpBB forum.
Would it be possible for my registered users to use the phpBB forum software to upload a GPX file and show the track on a OpenStreetMap map? Can this be done with BBcode?
So, is there a way of using GPXTrackMap with a forum?