def raw(rawfile,
channel=120,
transitspeed=3,
calfile=None,
soundspeed=None,
absorption=None,
preraw=None):
"""
Read EK60 raw data.
"""
# -------------------------------------------------------------------------
# load rawfile
ek60 = EK60.EK60()
ek60.read_raw(rawfile)
# -------------------------------------------------------------------------
# read frequency channel data
logger.info('Reading File ' + rawfile.split('/')[-1] + '...')
ch = None
for i in ek60.channel_id_map:
if str(channel) + ' kHz' in ek60.channel_id_map[i]:
ch = i
break
if ch is None:
sys.exit(str(channel) + ' kHz channel not found!')
raw = ek60.get_raw_data(channel_number=ch)
# -------------------------------------------------------------------------
# apply 38 kHz calibration parameters
if calfile is not None:
params = readCAL.ices(calfile, channel)
# -------------------------------------------------------------------------
# correct data for speed of sound and absorption
if 'params' not in locals():
class params(object):
pass
if soundspeed is not None:
params.sound_velocity = soundspeed
if absorption is not None:
params.absorption_coefficient = absorption
# -------------------------------------------------------------------------
# get raw data
Sv = np.transpose(raw.get_Sv(calibration=params).data)
theta = np.transpose(raw.angles_alongship_e)
phi = np.transpose(raw.angles_athwartship_e)
t = raw.get_Sv(calibration=params).ping_time
r = raw.get_Sv(calibration=params).range
alpha = raw.absorption_coefficient[0]
# -------------------------------------------------------------------------
# check continuity with preceeding RAW file
if preraw is None:
logger.warn('no preceding RAW file')
continuous = False
else:
pingrate = np.float64(np.mean(np.diff(t)))
timelapse = np.float64(t[0] - preraw['t'][-1])
if timelapse <= 0:
logger.warn('no preceding RAW file')
continuous = False
else:
if timelapse > 1.5 * pingrate:
logger.warn('time breach in preceding RAW file')
continuous = False
else:
if preraw['r'].size != r.size:
logger.warn('range discrepancy in preceding RAW file')
continuous = False
else:
if (preraw['r'] != r).all():
logger.warn('range discrepancy in preceding RAW file')
continuous = False
else:
continuous = True
# -------------------------------------------------------------------------
# get nmea data
transect, Tpos, LON, LAT, lon, lat, nm, km, kph, knt = nmea(ek60,
t,
preraw=preraw)
if preraw is not None:
if transect != preraw['transect']:
continuous = False
# -------------------------------------------------------------------------
# if not continuous, resume distances an start a new transect
if not continuous:
km -= np.nanmin(km)
nm -= np.nanmin(nm)
if preraw is not None:
if transect == preraw['transect']:
transect += 1
# -------------------------------------------------------------------------
# if stationary, turn transect number to negative & resume distances
if (nm[-1] - nm[0]) / (np.float64(t[-1] - t[0]) /
(1000 * 60 * 60)) < transitspeed:
km -= np.nanmin(km)
nm -= np.nanmin(nm)
if preraw is None:
transect = 0
else:
if preraw['transect'] > 0:
transect = -preraw['transect']
else:
transect = preraw['transect']
# -------------------------------------------------------------------------
# if just went off station, go to next transect number & resume distances
else:
if preraw is not None:
if (transect > 0) & (preraw['transect'] <= 0):
transect += 1
km -= np.nanmin(km)
nm -= np.nanmin(nm)
Tmot, PITCH, ROLL, HEAVE, pitch, roll, heave, pitchmax, rollmax, heavemax = motion(
ek60, t, preraw=preraw)
# -------------------------------------------------------------------------
# delete objects to free up memory RAM
del ek60, raw
# -------------------------------------------------------------------------
# return RAW data
raw = {
'rawfiles': [os.path.split(rawfile)[-1]],
'continuous': continuous,
'transect': transect,
'Sv': Sv,
'theta': theta,
'phi': phi,
'alpha': alpha,
'r': r,
't': t,
'lon': lon,
'lat': lat,
'nm': nm,
'km': km,
'kph': kph,
'knt': knt,
'pitch': pitch,
'roll': roll,
'heave': heave,
'pitchmax': pitchmax,
'rollmax': rollmax,
'heavemax': heavemax,
'Tpos': Tpos,
'LON': LON,
'LAT': LAT,
'Tmot': Tmot,
'PITCH': PITCH,
'ROLL': ROLL,
'HEAVE': HEAVE
}
return raw
example is to verify basic operation of the insert and delete methods,
but it also provides some simple and somewhat contrived examples of using
index arrays with these methods.
Note that the Echogram class doesn't always handle ping times that are NaT
very well so the X axis doesn't always get labeled properly in this example.
"""
import numpy as np
from matplotlib.pyplot import figure, show, subplots_adjust
from echolab2.instruments import EK60
from echolab2.plotting.matplotlib import echogram
# Read in some data from files.
rawfiles = ['./data/EK60/DY1201_EK60-D20120214-T231011.raw']
ek60 = EK60.EK60()
ek60.read_raw(rawfiles)
# Get a reference to the raw_data object.
raw_data_38 = ek60.get_raw_data(channel_number=2)
print(raw_data_38)
# Insert synthetic data. Create data where each ping is a constant value and
# the values change significantly from ping to ping so it is easy to
# distinguish the pings and verify (or not) that data is in the right place.
fake_data = np.arange(20) * 9.0 - 150.0
j = 0
for i in range(raw_data_38.n_pings):
raw_data_38.power[i, :] = fake_data[j]
j += 1
if j == fake_data.shape[0]:
def write(rawdir, save=False, txtfile='filereport.txt',
maxspeed=20, precision=8, bathymetry=None):
"""
Write a report with NMEA and CONFIG information for each RAW file contained
in a directory.
Args:
rawdir (str ): Directory were the RAW files are stored.
save (bool): Whether or not to save data as a text file in rawdir.
txtfile (str ): Name of text file created.
maxspeed (int ): Max speed permited in knots. Above this, it will
be considered an error and set to NAN.
precision (int): Decimal precision of data printed.
bathyrmetry (str): path/to/bathymetry/GEBCO.nc (default: None)
Returns:
Pandas.DataFrame: Report with the following tabular data:
* file : Name of RAW file
* y0 : start year (years after AD epoch)
* y1 : end year (years after AD epoch)
* d0 : start day (day of year)
* d1 : end day (day of year)
* h0 : start time (decimal hours)
* h1 : end time (decimal hours)
* sun0 : sun altitude at the start (degreses)
* sun1 : sun altitude at the end (degrees)
* seabed: seabed depth, estimated from bathymetry (m)
* lonmin: longitude minimum (decimal degrees)
* lonp25: longitude percentile 25 (decimal degrees)
* lonmed: longitude median (decimal degrees)
* lonp75: longitude percentile 75 (decimal degrees)
* lonmax: longitude maximum (decimal degrees)
* latmin: latitude minimum (decimal degrees)
* latp25: latitude percentile 25 (decimal degrees)
* latmed: latitude median (decimal degrees)
* latp75: latitude percentile 75 (decimal degrees)
* latmax: latitude maximum (decimal degrees)
* kntmin: speed minimum (knots)
* kntp25: speed percentile 25 (knots)
* kntmed: speed median (knots)
* kntp75: speed percentile 75 (knots)
* kntmax: speed maximum (knots)
* f18 : Presence of 18 kHz frequency (boolean)
* p18 : Power at 18 kHz (w)
* l18 : Pulse length at 18 kHz (m)
* i18 : Sample interval at 18 kHz (m)
* c18 : Sample count at 18 kHz)
* f38 : Presence of 38 kHz frequency (boolean)
* p38 : Power at 38 kHz (w)
* l38 : Pulse length at 38 kHz (m)
* i38 : Sample interval at 38 kHz (m)
* c38 : Sample count at 38 kHz
* f70 : Presence of 70 kHz frequency (boolean)
* p70 : Power at 70 kHz (w)
* l70 : Pulse length at 70 kHz (m)
* i70 : Sample interval at 70 kHz (m)
* c70 : Sample count at 70 kHz
* f120 : Presence of 120 kHz frequency (boolean)
* p120 : Power at 120 kHz (w)
* l120 : Pulse length at 120 kHz (m)
* i120 : Sample interval at 120 kHz (m)
* c120 : Sample count at 120 kHz
* f200 : Presence of 200 kHz frequency (boolean)
* p200 : Power at 200 kHz (w)
* l200 : Pulse length at 200 kHz (m)
* i200 : Sample interval at 200 kHz (m)
* c200 : Sample count at 200 kHz
* f333 : Presence of 333 kHz frequency (boolean)
* p333 : Power at 333 kHz (w)
* l333 : Pulse length at 333 kHz (m)
* i333 : Sample interval at 333 kHz (m)
* c333 : Sample count at 333 kHz
"""
# load bathymetry file and preallocate bathymetry data
if bathymetry:
bfile = xarray.open_dataset(bathymetry, chunks={'lon':360,'lat':180})
bdata = None
# look for RAW files in the directory
rawfiles = np.sort(glob.glob(os.path.join(rawdir, '*.raw')))
if not len(rawfiles):
raise Exception('No RAW files in directory %s' % rawdir)
# create data frame and declare columns names
pd.set_option('precision', precision)
df = pd.DataFrame(columns=[
'file' ,
'y0' ,'y1' ,
'd0' ,'d1' ,
'h0' ,'h1' ,
'sun0' ,'sun1' ,
'seabed',
'lonmin','lonp25','lonmed','lonp75','lonmax',
'latmin','latp25','latmed','latp75','latmax',
'kntmin','kntp25','kntmed','kntp75','kntmax',
'f18' ,'f38' ,'f70' ,'f120' ,'f200' ,'f333',
'p18' ,'p38' ,'p70' ,'p120' ,'p200' ,'p333',
'l18' ,'l38' ,'l70' ,'l120' ,'l200' ,'l333',
'i18' ,'i38' ,'i70' ,'i120' ,'i200' ,'i333',
'c18' ,'c38' ,'c70' ,'c120' ,'c200' ,'c333'])
# iterate through RAW files
errors = []
for i, rawfile in enumerate(rawfiles):
print('%s of %s: Collecting summary data from file %s' %
(i+1, len(rawfiles), os.path.split(rawfile)[-1]))
# load RAW file
try:
ek60 = EK60.EK60()
ek60.read_raw(rawfile)
# if error, add empty row to the data frame, log error, and continue
except Exception:
print('Unable to read file %s' %
os.path.split(rawfile)[-1])
df.loc[i] = [os.path.split(rawfile)[-1]]+['']*(df.shape[1]-1)
errors.append(os.path.split(rawfile)[-1])
continue
# get year, day of year, and decimal hour from start datetime
dt0 = ek60.start_time
dt0 = pd.DatetimeIndex([dt0])
y0 = np.int64(dt0.year)[0]
d0 = np.int64(dt0.dayofyear)[0]
h0 = np.float64(dt0.hour
+ dt0.minute /60
+ dt0.second /3600
+ dt0.microsecond/3600e6)[0]
# get year, day of year, and decimal hour from end datetime
dt1 = ek60.end_time
dt1 = pd.DatetimeIndex([dt1])
y1 = np.int64(dt1.year)[0]
d1 = np.int64(dt1.dayofyear)[0]
h1 = np.float64(dt1.hour
+ dt1.minute /60
+ dt1.second /3600
+ dt1.microsecond/3600e6)[0]
# explore NMEA messages to get position data, break when got it
for msg in ['GGA', 'GLL', 'RMC']:
time= ek60.nmea_data.get_datagrams(msg,return_fields=['Time'])
time= time[msg]['time']
lon = ek60.nmea_data.get_datagrams(msg,return_fields=['longitude'])
lon = lon[msg]['longitude']
lat = ek60.nmea_data.get_datagrams(msg,return_fields=['latitude'])
lat = lat[msg]['latitude' ]
if (isinstance(time, np.ndarray)&
isinstance(lon , np.ndarray)&
isinstance(lat , np.ndarray)):
break
# set metrics to NAN if NMEA data was not found
if (time is None)|(lon is None)|(lat is None):
nan= np.nan
sun0 , sun1 = nan, nan
seabed = nan
lonmin, lonp25, lonmed, lonp75, lonmax = nan, nan, nan, nan, nan
latmin, latp25, latmed, latp75, latmax = nan, nan, nan, nan, nan
kntmin, kntp25, kntmed, kntp75, kntmax = nan, nan, nan, nan, nan
warnings.warn('NMEA position data not found', Warning)
# calculate metrics otherwise
else:
# allocate longitude metrics
lonmin = np.min(lon)
lonp25 = np.percentile(lon, 25)
lonmed = np.median(lon)
lonp75 = np.percentile(lon, 75)
lonmax = np.max(lon)
# allocate latitude metrics
latmin = np.min(lat)
latp25 = np.percentile(lat, 25)
latmed = np.median(lat)
latp75 = np.percentile(lat, 75)
latmax = np.max(lat)
# calculate speed in knots
nmi = np.zeros(len(lon))*np.nan
for j in range(len(lon)-1):
if np.isnan(np.array([lon[j],lon[j+1],lat[j],lat[j+1]])).any():
nmi[j+1] = np.nan
else:
nmi[j+1] = distance((lat[j],lon[j]),(lat[j+1],lon[j+1])).nm
knt = np.r_[np.nan, nmi[1:]/(np.float64(np.diff(time))/1000)*3600]
# remove values above max speed
if (knt[~np.isnan(knt)]>maxspeed).any():
warnings.warn('%s speeds out of %s above max speed: set to NAN'
% (sum(knt[~np.isnan(knt)]>maxspeed), len(nmi)),
Warning)
knt[np.ma.masked_greater(knt, maxspeed).mask] = np.nan
# allocate speed metrics
kntmin = np.nanmin(knt)
kntp25 = np.nanpercentile(knt, 25)
kntmed = np.nanmedian(knt)
kntp75 = np.nanpercentile(knt, 75)
kntmax = np.nanmax(knt)
# get sun altitude in degrees with respect to platform positions
# at the first and last timestamp.
p0 = ephem.Observer()
p0.lon = str(lon[0])
p0.lat = str(lat[0])
p0.date = pd.to_datetime(time[0]).strftime('%Y/%m/%d %H:%M:%S')
sun0str = str(ephem.Sun(p0).alt)
deg0 = float(sun0str.split(':')[0])
min0 = float(sun0str.split(':')[1])
sec0 = float(sun0str.split(':')[2])
sun0 = deg0 + min0/60 + sec0/3600
p1 = ephem.Observer()
p1.lon = str(lon[-1])
p1.lat = str(lat[-1])
p1.date = pd.to_datetime(time[-1]).strftime('%Y/%m/%d %H:%M:%S')
sun1str = str(ephem.Sun(p1).alt)
deg1 = float(sun1str.split(':')[0])
min1 = float(sun1str.split(':')[1])
sec1 = float(sun1str.split(':')[2])
sun1 = deg1 + min1/60 + sec1/3600
# estimate seabed depth
if bathymetry:
# load bathymetry data if not done yet
if bdata is None:
c = (lonmed-1,lonmed+1,latmed+1,latmed-1) # W, E, N, S
print('Loading bathymetry [%2.2fW, %2.2fE, %2.2fN, %2.2fS]...'%c)
bdata = bfile.where((c[0]<bfile.lon)&(bfile.lon<c[1])&
(c[3]<bfile.lat)&(bfile.lat<c[2]),
drop=True)
blon = bdata.lon.data
blat = bdata.lat.data
bele = bdata.elevation.data.compute()
# use bathymetry to estimate seabed at RAW file's position
f = interp2d(blon, blat, bele, bounds_error=True)
try:
seabed = int(f(lonmed,latmed)[0])
# reload bathymetry if file's position falls outside the area
except ValueError:
c = (lonmed-1,lonmed+1,latmed+1,latmed-1) # W, E, N, S
print('Reloading bathymetry [%sW, %sE, %sN, %sS]...'%c)
bdata = bfile.where((c[0]<bfile.lon)&(bfile.lon<c[1])&
(c[3]<bfile.lat)&(bfile.lat<c[2]),
drop=True)
blon = bdata.lon.data
blat = bdata.lat.data
bele = bdata.elevation.data.compute()
f = interp2d(blon, blat, bele, bounds_error=True)
seabed = int(f(lonmed,latmed)[0])
# fill seabed depth with NAN, if bathymetry is not provided
else:
seabed=np.nan
# collect configuration for each frequency
f18,f38,f70,f120,f200,f333 = 0, 0, 0, 0, 0, 0
p18,p38,p70,p120,p200,p333 = np.nan,np.nan,np.nan,np.nan,np.nan,np.nan
l18,l38,l70,l120,l200,l333 = np.nan,np.nan,np.nan,np.nan,np.nan,np.nan
i18,i38,i70,i120,i200,i333 = np.nan,np.nan,np.nan,np.nan,np.nan,np.nan
c18,c38,c70,c120,c200,c333 = np.nan,np.nan,np.nan,np.nan,np.nan,np.nan
for ch, freq in enumerate(ek60.channel_ids):
# at 18 kHz
if '18 kHz' in freq:
f18 = ek60.get_raw_data(channel_number=ch+1)
if len(np.unique(f18.transmit_power))==1:
p18 = f18.transmit_power[0]
else:
p18 = -1
if len(np.unique(f18.pulse_length))==1:
l18 = f18.pulse_length[0]
else:
l18 = -1
if len(np.unique(f18.sample_interval))==1:
i18 = f18.sample_interval[0]
else:
i18 = -1
if len(np.unique(f18.sample_count))==1:
c18 = f18.sample_count[0]
else:
c18 = -1
f18 = 1
# at 38 kHz
if '38 kHz' in freq:
f38 = ek60.get_raw_data(channel_number=ch+1)
if len(np.unique(f38.transmit_power))==1:
p38 = f38.transmit_power[0]
else:
p38 = -1
if len(np.unique(f38.pulse_length))==1:
l38 = f38.pulse_length[0]
else:
l38 = -1
if len(np.unique(f38.sample_interval))==1:
i38 = f38.sample_interval[0]
else:
i38 = -1
if len(np.unique(f38.sample_count))==1:
c38 = f38.sample_count[0]
else:
c38 = -1
f38 = 1
# at 70 kHz
if '70 kHz' in freq:
f70 = ek60.get_raw_data(channel_number=ch+1)
if len(np.unique(f70.transmit_power))==1:
p70 = f70.transmit_power[0]
else:
p70 = -1
if len(np.unique(f70.pulse_length))==1:
l70 = f70.pulse_length[0]
else:
l70 = -1
if len(np.unique(f70.sample_interval))==1:
i70 = f70.sample_interval[0]
else:
i70 = -1
if len(np.unique(f70.sample_count))==1:
c70 = f70.sample_count[0]
else:
c70 = -1
f70 = 1
# at 120 kHz
if '120 kHz' in freq:
f120 = ek60.get_raw_data(channel_number=ch+1)
if len(np.unique(f120.transmit_power))==1:
p120 = f120.transmit_power[0]
else:
p120 = -1
if len(np.unique(f120.pulse_length))==1:
l120 = f120.pulse_length[0]
else:
l120 = -1
if len(np.unique(f120.sample_interval))==1:
i120 = f120.sample_interval[0]
else:
i120 = -1
if len(np.unique(f120.sample_count))==1:
c120 = f120.sample_count[0]
else:
c120 = -1
f120 = 1
# at 200 kHz
if '200 kHz' in freq:
f200 = ek60.get_raw_data(channel_number=ch+1)
if len(np.unique(f200.transmit_power))==1:
p200 = f200.transmit_power[0]
else:
p200 = -1
if len(np.unique(f200.pulse_length))==1:
l200 = f200.pulse_length[0]
else:
l200 = -1
if len(np.unique(f200.sample_interval))==1:
i200 = f200.sample_interval[0]
else:
i200 = -1
if len(np.unique(f200.sample_count))==1:
c200 = f200.sample_count[0]
else:
c200 = -1
f200 = 1
# at 333 kHz
if '333 kHz' in freq:
f333 = ek60.get_raw_data(channel_number=ch+1)
if len(np.unique(f333.transmit_power))==1:
p333 = f333.transmit_power[0]
else:
p333 = -1
if len(np.unique(f333.pulse_length))==1:
l333 = f333.pulse_length[0]
else:
l333 = -1
if len(np.unique(f333.sample_interval))==1:
i333 = f333.sample_interval[0]
else:
i333 = -1
if len(np.unique(f333.sample_count))==1:
c333 = f333.sample_count[0]
else:
c333 = -1
f333 = 1
# add new row of data to dataframe
df.loc[i] = [os.path.split(rawfile)[-1],
y0 , y1 ,
d0 , d1 ,
h0 , h1 ,
sun0 , sun1 ,
seabed,
lonmin, lonp25, lonmed, lonp75, lonmax,
latmin, latp25, latmed, latp75, latmax,
kntmin, kntp25, kntmed, kntp75, kntmax,
f18 , f38 , f70 , f120 , f200 , f333,
p18 , p38 , p70 , p120 , p200 , p333,
l18 , l38 , l70 , l120 , l200 , l333,
i18 , i38 , i70 , i120 , i200 , i333,
c18 , c38 , c70 , c120 , c200 , c333]
# save data frame as a text file
if save:
with open(os.path.join(rawdir, txtfile), 'w+') as f:
# write header
f.write('# NMEA AND CONFIGURATION DATA SUMMARY:\n')
f.write('# Variable names per column, from left to right:\n')
f.write('# * file : Name of RAW file\n')
f.write('# * y0 : start year (years after AD epoch)\n')
f.write('# * y1 : end year (years after AD epoch)\n')
f.write('# * d0 : start day (day of year)\n')
f.write('# * d1 : end day (day of year)\n')
f.write('# * h0 : start time (decimal hours)\n')
f.write('# * h1 : end time (decimal hours)\n')
f.write('# * sun0 : sun altitude at the start (degreses)\n')
f.write('# * sun1 : sun altitude at the end (degrees)\n')
f.write('# * seabed: seabed depth, estimated from bathymetry (m)\n')
f.write('# * lonmin: longitude minimum (decimal degrees)\n')
f.write('# * lonp25: longitude percentile 25 (decimal degrees)\n')
f.write('# * lonmed: longitude median (decimal degrees)\n')
f.write('# * lonp75: longitude percentile 75 (decimal degrees)\n')
f.write('# * lonmax: longitude maximum (decimal degrees)\n')
f.write('# * latmin: latitude minimum (decimal degrees)\n')
f.write('# * latp25: latitude percentile 25 (decimal degrees)\n')
f.write('# * latmed: latitude median (decimal degrees)\n')
f.write('# * latp75: latitude percentile 75 (decimal degrees)\n')
f.write('# * latmax: latitude maximum (decimal degrees)\n')
f.write('# * kntmin: speed minimum (knots)\n')
f.write('# * kntp25: speed percentile 25 (knots)\n')
f.write('# * kntmed: speed median (knots)\n')
f.write('# * kntp75: speed percentile 75 (knots)\n')
f.write('# * kntmax: speed maximum (knots)\n')
f.write('# * f18 : Presence of 18 kHz frequency (boolean)\n')
f.write('# * f38 : Presence of 38 kHz frequency (boolean)\n')
f.write('# * f70 : Presence of 70 kHz frequency (boolean)\n')
f.write('# * f120 : Presence of 120 kHz frequency (boolean)\n')
f.write('# * f200 : Presence of 200 kHz frequency (boolean)\n')
f.write('# * f333 : Presence of 333 kHz frequency (boolean)\n')
f.write('# * p18 : Power at 18 kHz (w). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * p38 : Power at 38 kHz (w). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * p70 : Power at 70 kHz (w). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * p120 : Power at 120 kHz (w). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * p200 : Power at 200 kHz (w). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * p333 : Power at 333 kHz (w). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * l18 : Pulse length at 18 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * l38 : Pulse length at 38 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * l70 : Pulse length at 70 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * l120 : Pulse length at 120 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * l200 : Pulse length at 200 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * l333 : Pulse length at 333 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * i18 : Sample interval at 18 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * i38 : Sample interval at 38 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * i70 : Sample interval at 70 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * i120 : Sample interval at 120 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * i200 : Sample interval at 200 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * i333 : Sample interval at 333 kHz (m). Fill value \'-1\' stands for \'variable\'\n')
f.write('# * c18 : Sample count at 18 kHz. Fill value \'-1\' stands for \'variable\'\n')
f.write('# * c38 : Sample count at 38 kHz. Fill value \'-1\' stands for \'variable\'\n')
f.write('# * c70 : Sample count at 70 kHz. Fill value \'-1\' stands for \'variable\'\n')
f.write('# * c120 : Sample count at 120 kHz. Fill value \'-1\' stands for \'variable\'\n')
f.write('# * c200 : Sample count at 200 kHz. Fill value \'-1\' stands for \'variable\'\n')
f.write('# * c333 : Sample count at 333 kHz. Fill value \'-1\' stands for \'variable\'\n')
f.write('\n')
# write data as comma-separated values (csv)
data = df.to_string(header=False, index=False).split('\n')
data = [','.join(x.split()) for x in data]
data = [x.replace('NaN','') for x in data]
for d in data:
f.write(d+'\n')
# report files not read due to reading errors
if errors:
print('Unable to read the following RAW files: %s' % errors)
print('%s files out of %s couldn\' be read!' %
(len(errors), len(rawfiles)))
# return dataframe
return df