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Convert lengths Biotic

Source: R/StoxBaselineFunctions.R
ConvertLengthBiotic.Rd

Convert lengths to approximate values for a desired length measurement. Typically 'total length'.

Usage

ConvertLengthBiotic(
  BioticData,
  LengthConversionTable,
  TargetLengthMeasurement = character()
)

Arguments

BioticData

BioticData for which lengths should be converted

LengthConversionTable

LengthConversionTable with parameters for converting lengths to 'TargetLengthMeasurement'.

TargetLengthMeasurement

The desired length measurement. Typically the code for 'total length'.

Value

BioticData with converted lengths.

Details

Different length measurements may be defined for fish, such as 'total length', 'standard length' or 'fork length'. For partially processed fish, only some measurements may be available, such as 'head-length'. When desired length measurment is not measured, 'total length' or some other length measurement may be approximated by a regression model.

For records where the variable 'catchcategory' on the table 'catchsample' matches the 'Species' variable in 'LengthConversionTable' this function converts lengths ('length' on the 'Individual'-table) to desired measurement type ('TargetLengthMeasurement') by matching the 'lengthmeasurement' variable on the corresponding 'catchsample'-table to 'MeasurementType' in 'LengthConversionTable' and applying the formula L_desired = 0.01 \* Alpha + Beta \* L_MeasurementType. The factor of 0.01 is applied because lengths in Biotic is defined i m, while 'Alpha' in 'LengthConversionTable' is defined in cm.

After conversion the 'lengthmeasurement'-variable will be changed to reflect the converted length. That is, they will be set to 'TargetLengthMeasurement'.

These variables are on these tables in data originating from NMDBiotic (http://www.imr.no/formats/nmdbiotic/). For bioticdata that does not conform to this, no modifications are done.

See also

DefineLengthConversionParameters for configuration of length parameters.