AIS Message Definitions

AIS Message: waterlevel (366:63:1)

Description:

Water level report. In this case from the NOAA Co-Ops 6 minute raw data. This is DRAFT/PROPOSED message format and should not be considered any sort of standard. The main goal is to illustrated the Tide Aware ENC and the AIS XML engine.

Note:Prototype only for the Hampton Roads/Elizabeth River 2007 demonstration project

See Also:http://opendap.co-ops.nos.noaa.gov/axis/

See Also:http://http://vislab-ccom.unh.edu/~schwehr/ais/waterlevel/

Name NumberOfBits ArrayLength Type Units Description
dac 10 uint Designated Area Code
fid 4 uint Functional Identifier
efid 12 uint extended functional identifier
timetag_month 4 uint Time the measurement represents month 1..12
timetag_day 5 uint Time the measurement represents day of the month 1..31
timetag_hour 5 uint Time the measurement represents UTC hours 0..23
timetag_min 6 uint Time the measurement represents minutes
timetag_sec 6 uint Time the measurement represents seconds
stationid 6 7 aisstr6 Character identifier of the station. Usually a number.
stationloc_longitude 28 decimal degrees Location of the sensor taking the water level measurement or position of prediction East West location
stationloc_latitude 27 decimal degrees Location of the sensor taking the water level measurement or position of prediction North South location
waterlevel 16 int cm Water level in centimeters
datum 5 uint What reference datum applies to the value
0: MLLW
1: IGLD-85
2: WaterDepth
3: STND
4: MHW
5: MLS
6: NGVD
7: NAVD
8: WGS-84
9: LAT
sigma 32 float m Standard deviation of 1 second samples used to compute the water level height
o 8 uint Count of number of samples that fall outside a 3-sigma band about the mean
levelinferred 1 bool indicates that the water level value has been inferred
flat_tolerance_exceeded 1 bool flat tolerance limit was exceeded. Need better descr
rate_tolerance_exceeded 1 bool rate of change tolerance limit was exceeded
temp_tolerance_exceeded 1 bool temperature difference tolerance limit was exceeded
expected_height_exceeded 1 bool either the maximum or minimum expected water level height limit was exceeded
link_down 1 bool Unable to communicate with the tide system. All data invalid
timeLastMeasured_month 4 uint Time since last measured value was available month 1..12
timeLastMeasured_day 5 uint Time since last measured value was available day of the month 1..31
timeLastMeasured_hour 5 uint Time since last measured value was available UTC hours 0..23
timeLastMeasured_min 6 uint Time since last measured value was available minutes
timeLastMeasured_sec 6 uint Time since last measured value was available seconds