Thanks for taking the time to open a feature request!

Is your feature request related to a problem? Please describe.
I'd like to be able to use a vanilla map id for an item join map, so for example, you could hold a map that tracks your position to then run commands. In my case, a map that tracks position could open a warps menu, then as I go to other parts of the world I see where I am on the map.

Describe the solution you'd like
To define a map id for filled_map items, that gives that exact map from vanilla

Describe alternatives you've considered
Could also define tracking/map centre within ItemJoin to then overlay the tracking on a custom image.

Added in b603.

Simply define map-id then your id.
Example; map-id: 0 (do note this only works if it is already rendered) otherwise you will be given a un rendered map but once the area is rendered it will ALWAYS be rendered for every player.

Hopefully, that makes sense, it essentially functions as a regular vanilla map, so if the map-id defined is NEW and not used then it creates a new canvas for the player location (just like a regular map item.)

Do note, if you define a custom-map-image for the item this will be negated.

Snapshot; https://ci.craftationgaming.com/job/ItemJoin/603/
Devlog; https://github.com/RockinChaos/ItemJoin/wiki/DevLog

This feature has been officially added in the release of ItemJoin v5.2.0.
You can grab it here; https://www.spigotmc.org/resources/itemjoin.12661/download?version=383801

Please read the changelog as the documentation has not been updated yet;
https://github.com/RockinChaos/ItemJoin/wiki/Recent-Changes