ProcessAZFP

class echopype.process.ProcessAZFP(file_path='', salinity=29.6, pressure=60, temperature=None)

Bases: echopype.process.processbase.ProcessBase

Class for manipulating AZFP echo data already converted to netCDF.

Attributes Summary

tilt_angle

Gets the tilt of the echosounder from the .nc file

Methods Summary

calc_range([tilt_corrected])	Calculates range in meters using AZFP-supplied formula, instead of from sample_interval directly.
calc_sample_thickness()	Gets sample_thickness for AZFP data.
calc_seawater_absorption([src])	Calculates seawater absorption in dB/km
calc_sound_speed([src])	Base method to be overridden for calculating sound_speed for different sonar models
calibrate([save, save_postfix, save_path])	Perform echo-integration to get volume backscattering strength (Sv) from AZFP power data.
calibrate_TS([save, save_postfix, save_path])	Perform echo-integration to get Target Strength (TS) from AZFP power data.

Attributes Documentation

tilt_angle

Gets the tilt of the echosounder from the .nc file

Returns

Tilt of echosounder in degrees

Methods Documentation

calc_range(tilt_corrected=False)

Calculates range in meters using AZFP-supplied formula, instead of from sample_interval directly.

Parameters

tilt_correctedbool

Modifies the range to take into account the tilt of the transducer. Defaults to False.

Returns

An xarray DataArray containing the range with coordinate frequency

calc_sample_thickness()

Gets sample_thickness for AZFP data.

This will call calc_sound_speed since sound speed is not part of the raw AZFP .01A data file.

calc_seawater_absorption(src='user')

Calculates seawater absorption in dB/km

Parameters

srcstr

‘file’ will return the seawater absoption recorded in the .nc file ‘user’ will calculate the seawater absorption. Default to AZFP provided formula.

formula_sourcestr

Select the formula used for calculating seawater absorption.

Returns

An xarray DataArray containing the sea absorption with coordinate frequency

calc_sound_speed(src='user')

Base method to be overridden for calculating sound_speed for different sonar models

calibrate(save=False, save_postfix='_Sv', save_path=None)

Perform echo-integration to get volume backscattering strength (Sv) from AZFP power data.

The calibration formula used here is documented in eq.(9) on p.85 of GU-100-AZFP-01-R50 Operator’s Manual. Note a Sv_offset factor that varies depending on frequency is used in the calibration as documented on p.90. See calc_Sv_offset() in convert/azfp.py

Parameters

savebool, optional

whether to save calibrated Sv output default to True

save_postfixstr

Filename postfix, default to ‘_Sv’

save_pathstr

Full filename to save to, overwriting the RAWFILE_Sv.nc default

calibrate_TS(save=False, save_postfix='_TS', save_path=None)

Perform echo-integration to get Target Strength (TS) from AZFP power data.

The calibration formula used here is documented in eq.(10) on p.85 of GU-100-AZFP-01-R50 Operator’s Manual.

Parameters

savebool, optional

whether to save calibrated TS output default to False

save_postfixstr, optional

Filename postfix, default to ‘_TS’

save_pathstr, optional

Full filename to save the TS calculation results, overwritting the RAWFILE_TS.nc default