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% Function to get the scattering, transmission and zscat from a binary (v. 2.05)
% LISST-100 or LISST-100X data file (.dat extension) and from a zscat file
% in either binary (.dat) or ASCII (.asc) format.
%
%  Usage:        [scat,tau,zsc,data,cscat] = getscat(‘datafile’,’zscfile’,X,’ringarefile’);
%
% Set X=1 for LISST-100X data, all other values for LISST-100 format
%
% Output:
% scat is the raw scattering signature in digital counts (i.e. NOT corrected
% with the ringarea file!!)
% tau is the optical transmission
% zsc is the loaded zscat
% data is the raw data file, converted from binary, or it can be a .LOG
% file
% cscat is the corrected scattering, computed if the ringarea file is
% supplied as input
%
% REQUIRED FILES: tt2mat.m
% Based on original getscat and getscatX by YCA
% Merged by OAM, April 14, 2008 to become version 2.0
% September 29, 2008: Added option to load datafiles as log files (OAM v. 2.05).
% August 18, 2010: Added option to output cscat if the ringarea file is
% specified (OAM v. 2.10)
% September 17, 2010: Added check to see if zscat file in dat format had
% more than 1 row. (OAM v. 2.11)
% March 10, 2011: Forced negative cscats to 0 (OAM)

function [scat,tau,zsc,data,cscat] = getscat(datafile,zscfile,X,ringareafile)
%check to see if at least 3 input arguments exists
if nargin < 3
error(‘You must specify at least datafile, zscfile, and X.’)
end

%check to see if cscat is being output if ringarea file is not supplied.
if nargin < 4
if nargout > 4
error(‘You have not specified a ringarea filename, yet have specified cscat as output. You must specify a ringarea file if you wish cscat to be output.’)
end
end

if nargin == 4
dcal = load(ringareafile);
end

%*******************************************************
%1: Load the zscat file in either binary or ASCII format
%*******************************************************
[pathstr, name, ext] = fileparts(zscfile);%get datafile info

if sum(strcmp(ext,{‘.asc’,’.ASC’}))>0;%if the zscat file is an ASCII file…
zsc=load(zscfile);%go ahead and load it
a = size(zsc,1);%get the number of rows in zsc
if (a~=1);%if the zsc file is in ASCII format there should only be one row and 40 columns
zsc = zsc’;%if not, transpose
end
else%if the zscat file is NOT an ASCII file then it can only be a .dat file
zsc = tt2mat(zscfile,40);%so read it using tt2mat
if X == 1;%do we have LISST-100X data format?
zsc(:,1:32) = zsc(:,1:32)/10;%then divide rings 1-32 by 10.
end
if size(zsc,1) > 1%are there more than 1 row in the zsc dat file? (OAM 9/17/10)
zsc = mean(zsc);%compute mean so that zsc always is a 1 x 40 vector
end
end
r = zsc(33)/zsc(36);%compute the laser power/laser reference ratio (to adjust for drift in laser output power over time)

%****************************
%2: Read the binary data file
%****************************
[pathstr, name, ext] = fileparts(datafile);%get datafile info
if sum(strcmp(ext,{‘.log’,’.LOG’}))>0;%if the data file is a log file
data=load(datafile);%load it right away
else
data = tt2mat(datafile,40);%read the binary data file using tt2mat
if X == 1;%do we have LISST-100X data format?
data(:,1:32) = data(:,1:32)./10;%then divide rings 1-32 by 10.
end
end
%note: log files are by default stored in LISST-100 format so they do
%not need to be divided by 10 after being loaded.

%************************************************************************
%3: Compute optical transmission, raw scattering, and cscat if applicable
%************************************************************************
tau = data(:,33)./r./data(:,36);%compute optical transmission, taking the eventual drift in laser power into account
row = size(data,1);
scat = zeros(row,32);%pre-allocate scat matrix

if nargin ~=4
for i = 1:row
scat(i,:)=data(i,1:32)/tau(i)-zsc(1:32)*data(i,36)/zsc(36);
end
else
cscat = zeros(row,32);%pre-allocate cscat matrix
for i = 1:row
scat(i,:)=data(i,1:32)/tau(i)-zsc(1:32)*data(i,36)/zsc(36);
cscat(i,:) = dcal.*scat(i,:);
end
cscat(cscat<0)=0;%negative cscats are not possible, so set them to 0.
end

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