title: Matlab using Interp1 for interpolation of matrx data set
body: <p>I have a large data set of offline and online data, offline data is only taken every two hourly so wish to interpolate between the gaps. where the data is missing it is replaced with -9.999. I wish to interpolate in order to estimate these values. My idea is to find the missing values in the set to compare against the time intervals, but I cannot get it to work</p>
  
  <p>This is what I have so far:</p>
  
  <pre><code>iv = 33; % column which holds cell weight
  ind = find (Data(:,iv)&lt;0);  % find the indices of missing values
  Interp_iv = interp1 (Data(ind,2),Data(ind,2),Data(:,2),'spline')
  </code></pre>