|Used for reference numbers or codes on winter sports features (ski pistes).|
|Used on these elements|
|Status: De facto|
|Tools for this tag|
"ref" stands for "reference" and is used for reference numbers of ski pistes.
Ski pistes are more than often materialized only in winter. User may want to use piste:ref=* instead of ref=* to tag the piste and not the underlying highway, where the reference is in use in summer.
This key has to be used in connection with the key piste:type=*.
See Also ref=*.