% PLOTWHEAT reads wheat.csv file with wheat data
% from http://www.globalfindata.com/ 
% 
% To make it more stationary:
% 1) Take logarithm of data,
% 2) Detrend the data.
% 
% (This is stored in matlab file wheat.mat)
%

% 20040202 Anders Malmberg

M = csvread('wheat.csv',1,1);
M = M(1:end-2,:);
% high, low, close

logM = log(M);
% use a rather long MA-filter inorder not
% to remove too much of the low frequencies
[data,trend] = detrendma(logM(:,3),20);

year = 1:size(M,1);
year = 1840+year;
plot(year,logM(:,3),'r',year,data,'k',year,trend,'m')
title('Wheat prices')
xlabel('Year')
ylabel('log(US Dollars/Pound)')
legend('Wheat Cash Price','Detrended','Trend')
grid on