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

#                    L A D C P P R O C . U T I L S 

#                    doc: Fri Mar 21 15:16:59 2014

#                    dlm: Sun Jul 27 17:00:57 2014

#                    (c) 2014 A.M. Thurnherr

#                    uE-Info: 14 49 NIL 0 0 72 2 2 4 NIL ofnI

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

# HISTORY:

#	Mar 21, 2014: - created

#				  - added rangeToBin()

#	Mar 27, 2014: - added rangeToBinAlongBeam()

#	Jul 27, 2014: - improved comments

#				  - moved depthOfGI() here from [LADCPproc.backscatter]

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

# calculate depth of particular bin in particular ensemble

# 	in contrast to the original UH code:

#		- the distance to the first bin is soundspeed-corrected

#		- instrument tilt is considered

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

sub depthOfBin($$)

{

	sub dzToBin($$)

	{

		my($ens,$bin) = @_;

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

		my($tlcorr) = cos(rad($LADCP{ENSEMBLE}[$ens]->{TILT}));

		return $sscorr*$tlcorr * ($LADCP{DISTANCE_TO_BIN1_CENTER} + $bin*$LADCP{BIN_LENGTH});

	}

	my($ens,$bin) = @_;

	return $LADCP{ENSEMBLE}[$ens]->{XDUCER_FACING_UP} ?

		   $LADCP{ENSEMBLE}[$ens]->{DEPTH} - &dzToBin($ens,$bin) :

		   $LADCP{ENSEMBLE}[$ens]->{DEPTH} + &dzToBin($ens,$bin);

}

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

# calculate along-beam distance between transducer and center of

# particular bin in particular ensemble

#	- used for acoustic backscatter correction

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

sub rangeToBin($$)

{

	my($ens,$bin) = @_;

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

	return $sscorr * ($LADCP{DISTANCE_TO_BIN1_CENTER} + $bin*$LADCP{BIN_LENGTH}) / cos(rad($LADCP{BEAM_ANGLE}));

}

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

# calculate depth of particular bin of particular beam in particular ensemble

#	- used to map acoustic backscatter of different beams correctly when

#	  instrument tilt is large

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

sub depthOfBinAlongBeam($$$)

{

	sub dzToBinAlongBeam($$$)

	{

		my($ens,$bin,$beam) = @_;

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

		my($pitch) = $LADCP{ENSEMBLE}[$ens]->{PITCH} + $pitch_offset;

		my($roll)  = $LADCP{ENSEMBLE}[$ens]->{ROLL}  + $roll_offset;

		if ($beam == 0) 	{ $roll  += $LADCP{BEAM_ANGLE}; }

		elsif ($beam == 1) 	{ $roll  -= $LADCP{BEAM_ANGLE}; }

		elsif ($beam == 2) 	{ $pitch += $LADCP{BEAM_ANGLE}; }

		else 				{ $pitch -= $LADCP{BEAM_ANGLE}; }

		my($tlcorr) = cos(rad(&angle_from_vertical($pitch,$roll)));

		return $sscorr*$tlcorr * ($LADCP{DISTANCE_TO_BIN1_CENTER} + $bin*$LADCP{BIN_LENGTH});

	}

	my($ens,$bin,$beam) = @_;

	return $LADCP{ENSEMBLE}[$ens]->{XDUCER_FACING_UP} ?

		   $LADCP{ENSEMBLE}[$ens]->{DEPTH} - &dzToBinAlongBeam($ens,$bin,$beam) :

		   $LADCP{ENSEMBLE}[$ens]->{DEPTH} + &dzToBinAlongBeam($ens,$bin,$beam);

}

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

# return center depth corresponding to particular grid index (in shear grid)

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

sub depthOfGI($) { return $_[0]*$GRID_DZ + $GRID_DZ/2; }		# depth corresponding to particular grid index

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

# return ocean velocity (u,v,w) at a given depth

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

sub oceanVel($)

{

}

1;