getTau

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   function [tau, az, el, Tground] = getTau(date, filename)

   function that reads an ASCII text file, given by filename, and finds the
   tau correction values that should be applied to the data for the
   time given by date

   sjcm

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0001 function [tau, az, el, Tground] = getTau(date, filename)
0002 
0003 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0004 %
0005 %   function [tau, az, el, Tground] = getTau(date, filename)
0006 %
0007 %   function that reads an ASCII text file, given by filename, and finds the
0008 %   tau correction values that should be applied to the data for the
0009 %   time given by date
0010 %
0011 %   sjcm
0012 %
0013 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0014 
0015 if(nargin<2)
0016   filename = 'constants/tau_values_ptcross.txt';
0017 end
0018 
0019 taus = load(filename);
0020 
0021 aDate  = taus(:,1);
0022 taus(:,1) = [];
0023 
0024 
0025 % first put things in chronological order
0026 [aDateChron, sortOrder] = sort(aDate);
0027 aChron     = taus(sortOrder,:);
0028 
0029 % redefine the variables
0030 aDate     = aDateChron;
0031 taus    = aChron;
0032 
0033 
0034 % let us get rid of the repeats - always trust the lastest one
0035 reps   = find(diff(aDate)==0);
0036 aDate(reps,:) = [];
0037 taus(reps,:) = [];
0038 
0039 % find the closest value to our desired date
0040 dateDif = aDate - repmat(date, size(aDate));
0041 f = find(dateDif > 0);
0042 if(isempty(f))
0043   f = length(dateDif);
0044 else
0045   f = f-1;
0046   f = f(1);
0047 end
0048 if(f==0)
0049   f=1;
0050 end
0051 
0052 tau = taus(f,:);
0053 finOrder = f;
0054 
0055 % check for nans
0056 if(any(isnan(tau)))
0057     display(['getTau:: Found some NaN values.']);
0058     display('getTau:: Will find previous good data');
0059     fNan = find(isnan(tau));
0060 
0061     for m=1:length(fNan)
0062         thisA = taus(:,fNan(m));
0063         if(all(isnan(thisA)))
0064             display('getTau::CAN''T DO SHIT!!!');
0065             error(['getTau:: ALL your R-factor corrections for this channel are bad']);
0066         end
0067         % since we have already cut the repeats, we can just use f as
0068         % our index to remove..
0069         newOrder = f;
0070         rVal = thisA(newOrder);
0071         while(isnan(rVal))
0072             newOrder = newOrder - 1;
0073             rVal = thisA(newOrder);
0074         end
0075         tau(fNan(m)) = rVal;
0076     end
0077 end
0078 
0079 % that is it
0080 az = tau(1);
0081 el = tau(2);
0082 Tground = tau(5:6);
0083 tau = tau(3:4);
0084 
0085 return;
0086