#!/usr/bin/perl

#======================================================================

#                    L A D C P P R O C 

#                    doc: Thu Sep 16 20:36:10 2010

#                    (c) 2010 A.M. Thurnherr

#======================================================================

# NOTES:

#   - the shear-method editing in this code is based on Eric Firing's merge.c

#   - as described in [LADCPproc.backscatter], there are three different codes 

#     for correcting echo amplitudes for attenuation loss & beam spreading

#   - comments starting with ## are taken verbatim from the original implementations

#   - the basic idea of the time lagging implemented in this code is similar

#     to the one implemented in Martin Visbeck's bestlag.m

#   - for SeaBird files:

#       - CTD elapsed time is estimated from recno * CTD{sampint}

#       - first elapsed time is added on output

#   - output elapsed time is from CTD to allow yoyo processing without loss of

#     time information

#   - CTD{elapsed} is undefined for records before instrument is in the water

#   - ITS-90 temp field in degC required

#   - salin field prequired

#   - pressure field in dbar required

#   - -i should be set to the number that's added to LADCP_elapsed to make the two

#     time series overplot nicely

# HISTORY:

#   Sep 16, 2010: - incepted

#   Oct 13, 2010: - first working version

#   Oct 14, 2010: - renamed from LADCPshear

#   Oct 19, 2010: - added -a)coustic backscatter profiles

#   Oct 20, 2010: - added -2)dary CTD sensors

#   Oct 23, 2010: - added magnetic-declination correction

#   Oct 26, 2010: - added tilt calculation

#   Dec  9, 2010: - added support for ASCII CTD files

#   Dec 10, 2010: - change -w) default to 120s

#                 - changed nshear output to 0 from nan when there are no samples

#   Dec 27, 2010: - changed sign of -l to accept lag output from [LADCP_w]

#   Jan 10, 2011: - -o => -k added new -o

#                 - added code to fill CTD sound vel gaps

#   Jan 22, 2011: - added -g) lat,lon

#                 - added -c)ompass corr

#   Jun 15, 2011: - added mean backscatter profile to default output

#   Jul  7, 2011: - added support for $BT_* processing parameters

#                 - replaced old per-bin acoustic backscatter profile output by

#                   acoustic backscatter depth-time-series

#                 - disabled seabed and acoustic backscatter code when not required (e.g. UL)

#                 - made non-diagnostic output terser

#   Jul 11, 2011: - changed default output to .tds and added -p)rofile option

#   Jul 14, 2011: - added -u)se D[eines1999][V[isbeck2004]]

#   Jul 15, 2011: - changed output bin# to 1-based in -a output

#                 - added T[hurnherr11] -u)se option

#                 - added $CTD{first_elapsed}

#   Jul 27, 2011: - replaced ndata by nsamp

#   Feb  5, 2012: - added profile max depth consistency check

#   Feb 19, 2912: - added elapsed time to shear profile output

#                 - replaced "nshear" output field by "nsamp"

#                 - BUG: bottom of profiles was incorrect when dc max depth > uc max depth

#                 - BUG: profile depth consistency check did not work for partial-depth yoyo casts

#   Apr 10, 2012: - changed default backscatter correction to Deines (1999)

#                 - improved and relaxed depth consistency check

#   Apr 11, 2012: - BUG: double comma that did not affect the output

#                 - BUG: code had assumed, but not ensured, that first CTD scan is valid

#   Apr 13, 2012: - removed -s argument from dependencies

#	Apr 17, 2012: - BAD BUG: magdec code call was bad and did not return correct value. ever.

#	Apr 18, 2012: - replaced Sv.n by Sv.nsamp

#	May 16, 2012: - adapted to ANTSlib V5.0

#				  - added support for -r)DI BT data

#				  - added $LADCP{MEAN_DT} from vertical-velocity code

#	May 17, 2012: - significantly relaxed profile-range consistency check (from 20% to 50%)

#					which is required for Dan Torres' shallow casts

#				  - added version info

#	May 18, 2012: - reduced "implausibly short cast" threshold to 5 min because of Dan's shallow casts

#	Jun 13, 2012: - added CTD_depth to tds output

#	Oct 28, 2012: - added -z

($ANTS)    = (`which ANTSlib` =~ m{^(.*)/[^/]*$});

($PERL_TOOLS) = (`which mkProfile` =~ m{^(.*)/[^/]*$});

($LADCPPROC)  = ($0 =~ m{^(.*)/[^/]*$});

require "$ANTS/ants.pl";

require "$ANTS/libEOS83.pl";

require "$ANTS/libstats.pl";

require "$LADCPPROC/LADCPproc.version";

require "$LADCPPROC/LADCPproc.loadCTD";

require "$LADCPPROC/LADCPproc.bestLag";

require "$LADCPPROC/LADCPproc.BT";

require "$LADCPPROC/LADCPproc.backscatter";

require "$LADCPPROC/LADCPproc.UHcode";

require "$PERL_TOOLS/RDI_BB_Read.pl";

require "$PERL_TOOLS/RDI_Coords.pl";

require "$PERL_TOOLS/RDI_Utils.pl";

$antsSummary = "$version -- process LADCP data to get shear, time series";

$antsParseHeader = 0;

&antsUsage('24a:b:c:df:g:i:kl:n:o:p:rs:t:u:w:z',2,

    '[use -2)dary CTD sensor pair]',

    '[require -4)-beam LADCP solutions]',

    '[use -r)DI bottom-track data]',

    '[-s)etup <file>] [-g)ps <lat,lon>]',

    '[-c)ompass-corr <offset,cos-fac,sin-fac>]',

    '[-o)utput grid <resolution[5m]>]',

    '[-i)nitial LADCP time lag <guestimate>]',

    '[-l)ag LADCP <by>] [auto-lag -w)indow <size[120s]>] [-n) <auto-lag windows[20]]',

    '[correct echo amplitude -u)sing D[eines99]|V[isbeck04]|T[hurnherr11]|n[ocorr]',

    '[-d)iagnostic screen output] [-z)oom through problems]',

    'output: [shear-p)rofile <file>] [-t)ime series <file>] [-f)lag <file>] [-b)ottom-track <file>]',

    '        [-a)coustic backscatter <dts-file] [bottom-trac-k) profs]',

    '<RDI file> <SeaBird file>');

$RDI_Coords::minValidVels = 4 if ($opt_4);

&antsFloatOpt($opt_l);

&antsCardOpt(\$opt_w,120);

    # old default of -w 30 does not work if there are significant ambiguity-velocity

    # problems, as is the case, e.g., with 2010_DIMES_US2 station 142

    # old default of -w 60 did not work for DIMES_UK2 station 4 (DL), possibly again

    # related to ambiguity velocity

&antsCardOpt(\$opt_n,20);

#&antsFileOpt($opt_s);      # DON'T, AS THIS WILL ADD AN UNWANTED DEPENDCY

&antsFloatOpt($opt_i);

&antsCardOpt(\$opt_o,5);

if (defined($opt_u)) {

    croak("$0: cannot decode -u $opt_u\n")

        unless ($opt_u =~ /^[dDvVtTn]/);

} else {

    $opt_u = 'Deines99';

}

if (defined($opt_g)) {

    ($CTD{lat},$CTD{lon}) = split(',',$opt_g);

    croak("$0: cannot decode -g $opt_g\n")

        unless numberp($CTD{lat}) && numberp($CTD{lon});

}

if (defined($opt_c)) {

    ($CC_offset,$CC_cos_fac,$CC_sin_fac) = split(',',$opt_c);

    croak("$0: cannot decode -c $opt_c\n")

        unless numberp($CC_offset) && numberp($CC_cos_fac) && numberp($CC_sin_fac);

}

$LADCP_file = &antsFileArg();

$CTD_file   = &antsFileArg();

&antsAddParams('LADCP_file',$LADCP_file,'CTD_file',$CTD_file);

&antsActivateOut();

#----------------------------------------------------------------------

# Step 1: Read LADCP Data

#----------------------------------------------------------------------

print(STDERR "Reading LADCP data ($LADCP_file)...");

readData($LADCP_file,\%LADCP);

printf(STDERR "\n\t%d ensembles",scalar(@{$LADCP{ENSEMBLE}})) if ($opt_d);

print(STDERR "\n");

#----------------------------------------------------------------------

# Step 2: Set Processing Parameters

#----------------------------------------------------------------------

print(STDERR "Setting processing parameters...\n");

printf(STDERR "\tloading $LADCPPROC/LADCPproc.defaults...\n");

require "$LADCPPROC/LADCPproc.defaults";

if (defined($opt_s)) {

    print(STDERR "\tloading $opt_s...\n");

    require $opt_s;

}

if ($LADCP{BLANKING_DISTANCE} == 0) {

    print(STDERR "\t\tBLANKING_DISTANCE == 0 => excluding all data from bin 1\n")

        if ($opt_d);

    $wbin_start = 2 unless ($wbin_start > 2);

    $ubin_start = 2 unless ($ubin_start > 2);

    $shbin_start = 2 unless ($shbin_start > 2);

    $BT_bin_start = 2 unless ($BT_bin_start > 2);

}

&antsAddParams('ADCP_orientation',

        $LADCP{ENSEMBLE}[0]->{XDUCER_FACING_UP} ? 'uplooker' : 'downlooker');

$SHEAR_PREGRID_DZ = 20;

$GRID_DZ = $opt_o;

#----------------------------------------------------------------------

# Step 3: Read CTD data

#----------------------------------------------------------------------

print(STDERR "Reading CTD data ($CTD_file)...");

readCTD($CTD_file,\%CTD);

printf(STDERR "\n\t%d scans",scalar(@{$CTD{press}})) if ($opt_d);

print(STDERR "\n");

my($year)  = substr($LADCP{ENSEMBLE}[0]->{DATE},6,4);

my($month) = substr($LADCP{ENSEMBLE}[0]->{DATE},0,2);

my($day  ) = substr($LADCP{ENSEMBLE}[0]->{DATE},3,2);

my($magdec,$maginc,$h_strength,$v_strength) = split('\s+',`magdec $CTD{lon} $CTD{lat} $year $month $day`);

croak("$0: unknown magnetic declination\n")

	unless defined($magdec);

&antsAddParams('magnetic_declination',$magdec);

#----------------------------------------------------------------------

# Step 4: Pre-Process CTD & LADCP Data

#----------------------------------------------------------------------

printf(STDERR "Pre-processing data...");

printf(STDERR "\n\tCTD...") if ($opt_d);

#------------------------

# clean CTD pressure data

#------------------------

my($pSpikes) = 0;

for (my($r)=1; $r<@{$CTD{press}}; $r++) {

	$pSpikes++,$CTD{press}[$r]=nan

		if (abs($CTD{press}[$r]-$CTD{press}[$r-1])/$CTD{sampint} > 2);

}

print(STDERR "\n\t\t$pSpikes CTD pressure spikes removed")

	if ($pSpikes>0 && $opt_d);

#-----------------------------------

# trim "preamble" without valid data

#-----------------------------------

my($r) = 0;

until (numberp($CTD{press}[$r]) && numberp($CTD{temp}[$r]) && numberp($CTD{salin}[$r])) { $r++ }

splice(@{$CTD{press}},0,$r);

splice(@{$CTD{temp}},0,$r);

splice(@{$CTD{salin}},0,$r);

print(STDERR "\n\t\t$r leading CTD scans without valid data removed")

	if ($r>0 && $opt_d);

#--------------------------------------------------

# calculate w and find deepest & shallowest records

#--------------------------------------------------

$CTD{maxpress} = -9e99;

$CTD{minpress} =  9e99;

for (my($r)=1; $r<@{$CTD{press}}-1; $r++) {

	$CTD{w}[$r] = 0.99*($CTD{press}[$r+1] - $CTD{press}[$r-1]) / (2*$CTD{sampint});

	if ($CTD{press}[$r] > $CTD{maxpress}) {

		$CTD{maxpress} = $CTD{press}[$r];

		$CTD{atbottom} = $r;

    }										

	if ($CTD{press}[$r] < $CTD{minpress}) {

		$CTD{minpress} = $CTD{press}[$r];

		$CTD{attop} = $r;

    }										

}

printf(STDERR "\n\t\tmin/max pressure [%d/%ddbar] at scans#%d/%d",

					$CTD{minpress},$CTD{maxpress},$CTD{attop},$CTD{atbottom})

	if $opt_d;

#----------------------------------------------------------------------

# Step 4b: Pre-Process LADCP Data

#----------------------------------------------------------------------

print(STDERR "\n\tLADCP...") if ($opt_d);

# transform to earth coordinates if required

$U = 0;		# velocity indices

$V = 1;

$W = 2;

$E = 3;

$LADCP{HEADING_BIAS} = -$magdec;

if ($LADCP{BEAM_COORDINATES}) {

	print(STDERR "\n\t\ttransforming beam to Earth coordinates...")

		if ($opt_d);

	for (my($ens)=0; $ens<=$#{$LADCP{ENSEMBLE}}; $ens++) {

		$LADCP{ENSEMBLE}[$ens]->{TILT} = &angle_from_vertical($LADCP{ENSEMBLE}[$ens]->{PITCH},$LADCP{ENSEMBLE}[$ens]->{ROLL});

		for (my($bin)=0; $bin<$LADCP{N_BINS}; $bin++) {

			@{$LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin]} =

				velInstrumentToEarth(\%LADCP,$ens,velBeamToInstrument(\%LADCP,@{$LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin]}));

			@{$LADCP{ENSEMBLE}[$ens]->{PERCENT_GOOD}[$bin]} =					# fake it to fool ref_lr_w

				(0,0,0,defined($LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin][$W]) ? 100 : 0);

		}

		@{$LADCP{ENSEMBLE}[$ens]->{BT_VELOCITY}} =

			velInstrumentToEarth(\%LADCP,$ens,velBeamToInstrument(\%LADCP,@{$LADCP{ENSEMBLE}[$ens]->{BT_VELOCITY}}));

	}

	$LADCP{BEAM_COORDINATES} = 0;

	$LADCP{EARTH_COORDINATES} = 1;

	unless ($opt_4) {

		print(STDERR "\n\t\t\t3-beam solutions: $RDI_Coords::threeBeam_1 $RDI_Coords::threeBeam_2 $RDI_Coords::threeBeam_3 $RDI_Coords::threeBeam_4\n")

			if ($opt_d);

		&antsAddParams('3_beam_solutions',"$RDI_Coords::threeBeam_1 $RDI_Coords::threeBeam_2 $RDI_Coords::threeBeam_3 $RDI_Coords::threeBeam_4");

	}

} elsif ($LADCP{EARTH_COORDINATES}) {

	if ($opt_d) {

		if ($opt_c) {

			printf(STDERR "\n\t\tcalculating tilt and correcting for compass error and magnetic declination of %.1f deg...\n",$magdec);

		} else {

			printf(STDERR "\n\t\tcalculating tilt and correcting for magnetic declination of %.1f deg...\n",$magdec);

		}

	}

	for (my($ens)=0; $ens<=$#{$LADCP{ENSEMBLE}}; $ens++) {

		$LADCP{ENSEMBLE}[$ens]->{TILT} = &angle_from_vertical($LADCP{ENSEMBLE}[$ens]->{PITCH},$LADCP{ENSEMBLE}[$ens]->{ROLL});

		my($hdg) = rad($LADCP{ENSEMBLE}[$ens]->{HEADING});

		$LADCP{HEADING_BIAS} = ($CC_offset + $CC_cos_fac*cos($hdg) + $CC_sin_fac*sin($hdg)) - $magdec

			if ($opt_c);

		for (my($bin)=0; $bin<$LADCP{N_BINS}; $bin++) {

			@{$LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin]} =

				velApplyHdgBias(\%LADCP,$ens,@{$LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin]});

		}

	}

} else {

	croak("$0: can only handle beam or earth coordinates\n")

}

#------------------------------------------------------

# construct a depth-vs-time "profile" from the raw data

#------------------------------------------------------

print(STDERR "\t\tconstructing profile time series...")

	if ($opt_d);

($LADCP_start,$LADCP_end,$LADCP_bottom,$w_gap_time,$zErr,$maxz) =

    mk_prof(\%LADCP,0,undef,1,6,70,0.1,9999);

croak("\n$LADCP_file: no good ensembles found\n")

    unless defined($LADCP_start);

my($cast_duration) = $LADCP{ENSEMBLE}[$LADCP_end]->{UNIX_TIME} -

                     $LADCP{ENSEMBLE}[$LADCP_start]->{UNIX_TIME};

croak("$0: implausibly short cast ($cast_duration seconds)\n")

	unless ($cast_duration > 300);

$LADCP{MEAN_DT} = $cast_duration / ($LADCP_end-$LADCP_start-1);

if ($opt_d) {

	printf(STDERR "\n\t\t\tStart of cast    : %s (#%5d) at %6.1fm\n",

	                    $LADCP{ENSEMBLE}[$LADCP_start]->{TIME},

	                    $LADCP{ENSEMBLE}[$LADCP_start]->{NUMBER},

	                    $LADCP{ENSEMBLE}[$LADCP_start]->{DEPTH});

	printf(STDERR "\t\t\tBottom of cast   : %s (#%5d) at %6.1fm\n",

	                    $LADCP{ENSEMBLE}[$LADCP_bottom]->{TIME},

	                    $LADCP{ENSEMBLE}[$LADCP_bottom]->{NUMBER},

	                    $LADCP{ENSEMBLE}[$LADCP_bottom]->{DEPTH});

	printf(STDERR "\t\t\tEnd of cast      : %s (#%5d) at %6.1fm\n",

	                    $LADCP{ENSEMBLE}[$LADCP_end]->{TIME},

	                    $LADCP{ENSEMBLE}[$LADCP_end]->{NUMBER},

	                    $LADCP{ENSEMBLE}[$LADCP_end]->{DEPTH});

	printf(STDERR "\t\t\tAvg ping interval: %.1fs",$LADCP{MEAN_DT});

}

print(STDERR "\n");

my($LADCP_prof_range) = $LADCP{ENSEMBLE}[$LADCP_bottom]->{DEPTH} -

							min($LADCP{ENSEMBLE}[$LADCP_start]->{DEPTH},$LADCP{ENSEMBLE}[$LADCP_end]->{DEPTH});

my($CTD_prof_range) = $CTD{maxpress} - $CTD{minpress};

croak(sprintf("$0: LADCP profile depth range (%dm) inconsistent with max CTD pressure range (%ddbar) [-z to disable]\n",

		$LADCP_prof_range,$CTD_prof_range))

	if (!$opt_z && abs($LADCP_prof_range-0.99*$CTD_prof_range) >

						max(0.2*0.99*$CTD_prof_range,abs($LADCP{ENSEMBLE}[$LADCP_end]->{DEPTH}),50));

#----------------------------------------------------------------------

# Step 5: Add CTD to LADCP Data & correct velocities for sound speed

#	- {DEPTH} field is overwritten!

#----------------------------------------------------------------------

print(STDERR "Matching CTD to LADCP time series...");

print(STDERR "\n") if defined($opt_l);

$opt_l = defined($opt_l) ? -$opt_l : &lagLADCP2CTD();

print(STDERR "Associating CTD data with LADCP ensembles...");

for (my($min_depth)=9e99,my($ens)=$LADCP_start; $ens<=$LADCP_end; $ens++) {

	my($lastSvel); 

	my($r) = int(($LADCP{ENSEMBLE}[$ens]->{ELAPSED_TIME} - $opt_l) / $CTD{sampint});

	if ($r < 0 && $ens == $LADCP_start) {

		$r = int(($LADCP{ENSEMBLE}[++$ens]->{ELAPSED_TIME} - $opt_l) / $CTD{sampint})

			while ($r < 0);

		printf(STDERR "\n\tCTD data begin with instrument already in water => skipping %ds of LADCP data",

			$LADCP{ENSEMBLE}[$ens]->{ELAPSED_TIME}-$LADCP{ENSEMBLE}[$LADCP_start]->{ELAPSED_TIME});

		$LADCP_start = $ens;

	}

	if ($r > $#{$CTD{press}}) {

		printf(STDERR "\n\tCTD data end while instrument is still in water => truncating %ds of LADCP data",

			$LADCP{ENSEMBLE}[$LADCP_end]->{ELAPSED_TIME}-$LADCP{ENSEMBLE}[$ens]->{ELAPSED_TIME})

				if ($opt_d);

		$LADCP_end = $ens - 1;

		last;

	}

	my($dr);

	for ($dr=0; !numberp($CTD{press}[$r+$dr]); $dr--) {}

	$LADCP{ENSEMBLE}[$ens]->{DEPTH} = depth($CTD{press}[$r+$dr],$CTD{lat});

	if ($LADCP{ENSEMBLE}[$ens]->{DEPTH} < $min_depth) {

		$min_depth = $LADCP{ENSEMBLE}[$ens]->{DEPTH};

		$LADCP_top = $ens;

	}

	$LADCP{ENSEMBLE}[$ens]->{CTD_W} = $CTD{w}[$r];

	$LADCP{ENSEMBLE}[$ens]->{CTD_TEMP} = $CTD{temp}[$r];

	$LADCP{ENSEMBLE}[$ens]->{CTD_SVEL} = sVel($CTD{salin}[$r],$CTD{temp}[$r],$CTD{press}[$r+$dr]);

	if (numberp($LADCP{ENSEMBLE}[$ens]->{CTD_SVEL})) {

		$lastSvel = $LADCP{ENSEMBLE}[$ens]->{CTD_SVEL};

	} else {

		$LADCP{ENSEMBLE}[$ens]->{CTD_SVEL} = $lastSvel;

	}

	my($sscorr) = $LADCP{ENSEMBLE}[$ens]->{CTD_SVEL} / $LADCP{ENSEMBLE}[$ens]->{SPEED_OF_SOUND};

	for (my($bin)=0; $bin<$LADCP{N_BINS}; $bin++) {

		next unless defined($LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin][$W]);

		$LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin][$U] *= $sscorr;

		$LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin][$V] *= $sscorr;

		$LADCP{ENSEMBLE}[$ens]->{VELOCITY}[$bin][$W] *= $sscorr;

    }

}

&antsAddParams('top_depth',round($LADCP{ENSEMBLE}[$LADCP_top]->{DEPTH}),

			   'bottom_depth',round($LADCP{ENSEMBLE}[$LADCP_bottom]->{DEPTH}),

			   'start_date',$LADCP{ENSEMBLE}[$LADCP_start]->{DATE},

			   'start_time',$LADCP{ENSEMBLE}[$LADCP_start]->{TIME},

			   'bottom_date',$LADCP{ENSEMBLE}[$LADCP_bottom]->{DATE},

			   'bottom_time',$LADCP{ENSEMBLE}[$LADCP_bottom]->{TIME},

			   'end_date',$LADCP{ENSEMBLE}[$LADCP_end]->{DATE},

			   'end_time',$LADCP{ENSEMBLE}[$LADCP_end]->{TIME});

print(STDERR "\n");

#----------------------------------------------------------------------

# Step 6: Calculate Acoustic Backscatter Profile

#----------------------------------------------------------------------

print(STDERR "Calculating acoustic backscatter profiles...");

mk_backscatter_profs($LADCP_start,$LADCP_end);

print(STDERR "\n");

#----------------------------------------------------------------------

# Step 7: Find Seabed

#----------------------------------------------------------------------

if ($LADCP{ENSEMBLE}[$LADCP_start]->{XDUCER_FACING_DOWN}) {

	print(STDERR "Finding seabed...");

	print(STDERR "\n\tin acoustic backscatter profiles...") if ($opt_d);

	($water_depth,$sig_water_depth) =

		find_backscatter_seabed($LADCP{ENSEMBLE}[$LADCP_bottom]->{DEPTH});

	printf(STDERR "\n\t\twater depth = %d(+-%.1f)m",$water_depth,$sig_water_depth)

		if ($opt_d);

	print(STDERR "\n\tin RDI BT data...") if ($opt_d);

	($BT_water_depth,$sig_BT_water_depth) = 

		find_seabed(\%LADCP,$LADCP_bottom,$LADCP{BEAM_COORDINATES});

	if (defined($BT_water_depth)) {

		printf(STDERR "\n\t\twater depth = %d(+-%.1f)m",$BT_water_depth,$sig_BT_water_depth)

			if ($opt_d);

	} else {

		printf(STDERR "\n\t\tno seabed found") if ($opt_d);

	}

	if ($opt_r) {													# use RDI BT data

		$water_depth = $BT_water_depth;

		$sig_water_depth = $sig_BT_water_depth;

    }

    $min_hab = $water_depth - $LADCP{ENSEMBLE}[$LADCP_bottom]->{DEPTH};

	if (defined($water_depth)) {

		printf(STDERR "\n\twater depth      = %d(+-%.1f)m",$water_depth,$sig_water_depth);

		printf(STDERR "\n\tclosest approach = %dmab",$min_hab);

    } else {	

		print(STDERR "\n\tno seabed found\n");

		print(STDERR "\n\tunknown water depth => PPI editing disabled\n")

			if ($opt_d);

		$clip_margin = 0;

	}

	print(STDERR "\n");

} else { # UPLOOKER

	$water_depth = $sig_water_depth = $min_hab = nan;

	print(STDERR "Uplooker data => PPI editing disabled\n")