Item E, F, G - vertical limits

As explained in the data encoding section, vertical limits are typically encoded in AIXM as a pair of two attributes:

a "...Limit" attribute, which includes the value and its unit of measurement (as an "uom" attribute) with the list of values: UomDistanceVerticalType;
a "...LimitReference" attribute, which indicates what reference system is used for the vertical limit value. It uses the following list of values: CodeVerticalReferenceType.

The following rules shall be applied for the automatic production of the NOTAM text (decoding of the vertical limits):

*"...Limit" Value*	*"...Limit" @uom*	*"...LimitReference"*	*Text to be inserted*
GND	any value or NIL	any value or NIL	"SFC"
UNL	any value or NIL	any value or NIL	"UNL"
FLOOR	any value or NIL	any value or NIL	"Its lower limit" (see Notes below)
CEILING	any value or NIL	any value or NIL	"Its upper limit" (see Notes below)
XXXXX	FT	SFC	"XXXXXFT AGL"
XXXXX	FT	MSL	"XXXXXFT AMSL"
XXXXX	FT	W84	"XXXXXFT above WGS-84 ellipsoid"
XXXXX	M	SFC	"XXXXXM AGL"
XXXXX	M	MSL	"XXXXXM AMSL"
XXXXX	M	W84	"XXXXXM above WGS-84 ellipsoid"
XXX	FL	STD	"FLXXX"
XXX	SM	STD	"SMXXX"

Notes:

The values FLOOR and CEILING will not occur in the items F or G, just in the decoding of vertical limits in item E of some particular scenarios;
The decoding for the values having as reference 'W84' is provided for completeness sake, but they will not occur in the current practice;
The decoding of "standard meters" (SM) is similar to the decoding of the FL values; although this value is not mentioned in the OPADD, there is no reason to exclude it from this decoding, for those regions that use SM instead of FL.