Coerce Data Into an echosounder Object

Coerces a dataset into a echosounder dataset.

Usage

as.echosounder(
  time,
  depth,
  a,
  src = "",
  sourceLevel = 220,
  receiverSensitivity = -55.4,
  transmitPower = 0,
  pulseDuration = 400,
  beamwidthX = 6.5,
  beamwidthY = 6.5,
  frequency = 41800,
  correction = 0
)

Arguments

time: times of pings.
depth: depths of samples within pings.
a: matrix of echo amplitudes, as would be stored with read.echosounder().
src: optional string indicating data source.
sourceLevel: source level, in dB (uPa at 1m), denoted sl in reference 1 p15, where it is in units 0.1dB (uPa at 1m).
receiverSensitivity: receiver sensitivity of the main element, in dB(counts/uPa), denoted rs in reference 1 p15, where it is in units of 0.1dB(counts/uPa)
transmitPower: transmit power reduction factor, in dB, denoted tpow in reference 1 p10, where it is in units 0.1 dB.
pulseDuration: duration of transmitted pulse in us
beamwidthX: x-axis -3dB one-way beamwidth in deg, denoted bwx in reference 1 p16, where the unit is 0.2 deg
beamwidthY: y-axis -3dB one-way beamwidth in deg, denoted bwx in reference 1 p16, where the unit is 0.2 deg
frequency: transducer frequency in Hz, denoted fq in reference 1 p16
correction: user-defined calibration correction in dB, denoted corr in reference 1 p14, where the unit is 0.01dB.

Value

An echosounder object.

Details

Creates an echosounder file. The defaults for e.g. transmitPower are taken from the echosounder dataset, and they are unlikely to make sense generally. The first three parameters must be supplied, and the dimension of a must align with the lengths of time and depths. The other parameters have defaults that are unlikely to be correct for arbitrary application, but they are not essential for basic plots, etc.

Those who use the readHAC package to read echosounder data should note that it stores the a matrix in a flipped and transposed format. See that package's demo code for a function named flip() that transforms the matrix as required by as.echosounder(). Indeed, users working with HAC data ought to study the whole of the readHAC documentation, to learn what data are stored, so that oceSetMetadata() and oceSetData() can be used as needed to flesh out the contents returned by as.echosounder().

Author

Dan Kelley