Attribute: Tide - time and height differences
Attribute type: A
time difference in hours and minutes: ± hhmm (according to ISO 8106: 1988) height difference: metres (preceded with "-" if negative value) rate difference: knots (preceded with "-" if negative value)
Tidal height: 63230, Darwin,-0040,-0.7,0.9
Tidal stream: 59060, Cairns,+0130,1.2,-0.7
The attribute 'tide - time and height differences' encodes the time and tidal height or tidal stream rat e difference comparative to a reference station.
The format is the same for tides and tidal streams, with height difference being replaced by rat e difference. The relation to a reference station is encoded by the use of a collection object.
The attribute is used to contain the identification of the reference station and , encoded in triplets, mean time difference (+ or -), height or rate difference for mean high water or mean high rate (preceded with "-" if negative value), height or rate difference for mean low water or mean low rate (preceded with "-" if negative value), each value separated by a comma.