% Sample code 22 Jan 2010, Professor Guth for SO503

% must open the first file with File, Import data
% Matlab does not like ASCII text for values in the file (after header row)
% Either remove the offending column before importing, or
%   convert the Text to a number with a global search and replace
% create a vector from each column of the data

%allocate storage for variables, and zero out the vectors
Hours=zeros(6051,1);
dx=zeros(6050,1);
dy=zeros(6050,1);     
heading=zeros(6050,1);
tc=zeros(6050,1);
speed=zeros(6050,1);
filhead=zeros(6050,1);

for i=1:6051,
   %don't have time to get the hours right, will come back and fix
   Hours(i) = 10 + i/3600;
end;
for i=1:6050,
   dx(i)=X_MERC(i+1)-X_MERC(i);
   dy(i)=Y_MERC(i+1)-Y_MERC(i);
   tc(i)=(Hours(i+1)+Hours(i))/2;
   heading(i)=atan2(dy(i),dx(i));
   heading(i)=rad2deg(heading(i));
   if heading(i) < 0,
      heading(i) = heading(i) + 360;
   else
      %no need here, we think
   end
end;
filsize=13
filhead=filter(ones(1,filsize)/filsize,1,heading);
f1=plot(tc,heading,tc,filhead);
xlabel('Time (hours)');