Map and origin point

A bounding box defining the position of an object seen in a sample. All location data is given with respect to the global coordinate system.
translation": [3] – Bounding box location as center_x, center_y, center_z.

what is center x , y, z according to the global coordinate system?
how can I locate the annotation in the map?
what is the origin of the map which all annotations are respected to it?

x, y, z are the distance from the map origin (longitude, latitude, height) in meters.
The origin is the same for all scenes from the same location.
There are 4 locations: boston-seaport, singapore-onenorth, singapore-hollandvillage, singapore-queenstown.
The origin of each map is a the beginning of the closest slippy tile ( at a particular zoom level.
I’ll try to figure out next week which latitude and longitude these correspond to,