MeanDensityData: Mean density data

In StoXProject/RstoxBase: Base StoX Functions

Mean density data

Description

The MeanDensityData model data holds the density of individuals as number per square nautical mile, by Stratum and Layer. The data type contains the tables Data and Resolution. The variables of the MeanDensityData are the same as in DensityData, except that the variable PSU is not present in the table Data, and that the variable DensityWeight is replaced by the variable MeanDensityWeight:

Details

Data:

Variable	Description	Unit	Data type	Example	Occurrence
Survey	The survey identifier	None	Character	"MainSurvey"	Always
Stratum	The stratum identifier	None	Character	"Stratum1"	Always
Layer	The depth Layer identifier	None	Character	"Layer1"	Always
Beam	Unique Beam identifier	None	Character	"38000/2"	AcousticDensity
SpeciesCategory	The species category	None	Character	"Herring"	Always
IndividualTotalLength	Total length (from snout to end of fin), given as the lower end of the interval of width given by LengthResolution	cm	Numeric	14.5	SweptAreaDensity
LengthResolution	Resolution of IndividualTotalLength	cm	Numeric	0.5	SweptAreaDensity
Frequency	The acoustic frequency of the Beam	hertz	Numeric	38000	AcousticDensity
Density	The density, either given as number of individuals or weight per square nautical mile (when DensityType is "AreaNumberDensity" or AreaWeightDensity, respectively)	nmi^-2 if DensityType is "AreaNumberDensity", and kg nmi^-2 if DensityType is "AreaWeightDensity" (only relevant when SweptAreaDensityMethod is "TotalCatch")	Numeric	123.4	Always
MinLayerDepth	The minimum depth of the depth Layer	m	Numeric	0	Always
MaxLayerDepth	The maximum depth of the depth Layer	m	Numeric	100	Always
MeanDensityWeight	The weight of the density value associated with the Stratum, i.e., the number of Stations for SweptAreaDensity and total LogDistance for AcousticDensity	None	Numeric	8	Always
DensityType	The type of density, currently one of "AreaNumberDensity" and "AreaWeightDensity"	None	Character	"AreaNumberDensity"	Always

Resolution:

Variable	Description	Unit	Data type	Example	Occurrence
Stratum	The stratum identifier	None	Character	"Stratum1"	Always
PSU	The PSU identifier	None	Character	"PSU1"	Always
EDSU	Unique elementary distance sampling unit (EDSU/Log) identifier	None	Character	"2020821/2020-04-24T03:51:26.000Z"	AcousticDensity
Station	Unique Station identifier	None	Character	"2021105-1"	SweptAreaDensity
Layer	The depth Layer identifier	None	Character	"Layer1"	Always
Channel	Unique NASC depth channel identifier	None	Character	"2"	AcousticDensity
Cruise	Unique Cruise identifier (see StoxAcousticFormat for output from AcousticDensity and StoxBioticFormat for output from SweptAreaDensity)	None	Character	"2021105"	Always
EffectiveLogDistance	The effective length of the EDSU	nmi	Numeric	0.09	AcousticDensity
EffectiveTowDistance	Effective tow distance of the Haul	nmi	Numeric	1.5	SweptAreaDensity
DateTime	UTC time at start of the EDSU or Station, stored as POSIXct	ISO8601	Character	2020-09-09T01:02:03.456Z	Always
Longitude	Longitude at start of the EDSU or Station	degree east	Numeric	62.5	Always
Latitude	Latitude at start of the EDSU or Station	degree north	Numeric	5.1	Always
VerticalNetOpening	Vertical span of the net	m	Numeric	23	SweptAreaDensity
HorizontalNetOpening	Vertical span of the net	m	Numeric	105	SweptAreaDensity
TrawlDoorSpread	Distance between the trawl doors.	m	Numeric	125	SweptAreaDensity

See Also

This data type is produced by MeanDensity based on DensityData See DataTypes for a list of all StoX data types produced by RstoxBase

StoXProject/RstoxBase documentation built on Nov. 6, 2024, noon