The MeanNASCData model data is a list of two elements; the Data, which are similar to NASCData
but added the Layer vertical resolution column and the Stratum and PSU horizontal resolution columns, and summed vertically and averaged horizontally; and the Resolution, which is a table of the five columns Stratum, PSU, EDSU, Layer and Channel containing the link between the horizontal and vertical resolution variables before summing and averaging.
Data:
Variable | Description | Unit | Data type | Example |
Survey | The survey identifier | None | Character | "MainSurvey" |
Stratum | The stratum identifier | None | Character | "Stratum1" |
PSU | The PSU identifier | None | Character | "PSU1" |
Layer | The depth Layer identifier | None | Character | "Layer1" |
Beam | Unique Beam identifier | None | Character | "38000/2" |
AcousticCategory | The acoustic category | None | Character | "HER" |
Frequency | The acoustic frequency of the Beam | hertz | Numeric | 38000 |
NASC | The nautical area scattering coefficient. | m^2/nmi^2 | Numeric | 59.24813 |
MinLayerDepth | The minimum depth of the depth Layer | m | Numeric | 0 |
MaxLayerDepth | The maximum depth of the depth Layer | m | Numeric | 100 |
MeanNASCWeight | The total LogDistance of the PSU | None | None | 0.1 |
ChannelReferenceType | Unique ChannelReference identifier | None | Character | "P" |
ChannelReferenceDepth | The depth of the ChannelReference origin. 0 for pelagic channels. Not yet given for bottom channels, as BottomDepth is not yet defined for NMDEchosounder data | m | Numeric | 0 |
ChannelReferenceTilt | The tilt angle of the beam, where 180 is vertically downwards and 0 is vertically upwards | degree | Numeric | 180 |
Resolution:
Variable | Description | Unit | Data type | Example |
Stratum | The stratum identifier | None | Character | "Stratum1" |
PSU | The PSU identifier | None | Character | "PSU1" |
EDSU | Unique elementary distance sampling unit (EDSU/Log) identifier | None | Character | "2020821/2020-04-24T03:51:26.000Z" |
Layer | The depth Layer identifier | None | Character | "Layer1" |
Channel | Unique NASC depth channel identifier | None | Character | "2" |
Cruise | Unique Cruise identifier (see StoxAcousticFormat for output from AcousticDensity and StoxBioticFormat for output from SweptAreaDensity ) | None | Character | "2021105" |
EffectiveLogDistance | The effective length of the EDSU | nmi | Numeric | 0.09 |
DateTime | UTC time at start of the EDSU or Station, stored as POSIXct | ISO8601 | Character | 2020-09-09T01:02:03.456Z |
Longitude | Longitude at start of the EDSU or Station | degree east | Numeric | 62.5 |
Latitude | Latitude at start of the EDSU or Station | degree north | Numeric | 5.1 |