ignore nan values in plotting

Hi!

I need your help please!

I have to plot columns with nan values. I want to ignore the nan. I have the table LOGIR who contains 2048 columns and the table XMEAN with one column. The XMEAN has no nan values. The LOGIR has nan. I want to plot XMEAN with each column of the LOGIR and then i do fitting linear. The problem is that the equation of line is y=nanx+nan, because include the nan values. How can i ignore the nan values??

My script is:

for k=159:100:2048
  p=polyfit(XMEAN,LOGIR(:,k),1);
  yfit=polyval(p,XMEAN);
  figure(k);
  plot(XMEAN,LOGIR(:,k),'.',XMEAN,yfit,'r');
  gtext(['y=',num2str(p(1)),'x+',num2str(p(2))])
  xlabel('airmass')
  ylabel('logirradiance')
  print(sprintf('Figure(%d).bmp',k), '-dbmp')
end

Thank you

Answer 1

[Fani]

It works!! Thank you very much!

[dpb]

Of course it works... :)

If it solved the problem, please Accept the answer so other folks know the subject is resolved...

Answer 2

[dpb]

In your loop over the columns

for k=159:100:2048
  p=polyfit(XMEAN,LOGIR(:,k),1);
  yfit=polyval(p,XMEAN);

handle the NaNs before trying to fit...

for k=159:100:2048
  ix=isfinite(LOGIR(:,k));    % indices of the non-NaN (finite) values 
  x=XMEAN(ix); y=LOGIR(ix,k); % save in a temporary array
  p=polyfit(x,y,1);
  yfit=polyval(p,x);
  ...