Intersection table representing the resolution of a many to many relationship.

esrf_feature_s (FSK, M: CHAR VARYING(19))
esrf_feature_t (M: CHAR VARYING(16))
coordinate_sys_id (FNK, M: CHAR VARYING(40))

coordinate_system.earth_surface_feature
These are the areas of the surface of the Earth that are defined as appropriate to use this coordinate system.
earth_surface_feature.coordinate_system
This describes the coordinate systems that have been defined as appropriate to this portion of the surface of the Earth.
esrf_feature_s: Implements a foreign key to a row in one of the tables projected from entity earth_surface_feature depending on the value of the next column (See below).
esrf_feature_t: Defines the name of the referenced table. Possible values are defined in @earth_surface_feature.
coordinate_sys_id: Defines the coordinate system of the coordinate value(s). Defines a foreign key to table coordinate_sys.