A server connection is required to share location. Servers contain "Networks" which are basically segments assigned for guilds. I offer networks for free on my server, if you need one. PM me the desired network name and password.
The map markers are a collaborative project. You are welcome to update them yourself and submit it to the github, but make sure that your update covers the entirety of the subject you cover (for example all dungeon gates) and that the locations are spot on. I'm not sure who made the original dungeon gate file - perhaps Dirk?
i did them originally, i'll update them one day unless someone gets to it before me, my mapper use has dwindled significantly as i have increased my familiarity with the map, so when i'll get around to it is a good question