Description interp1 interpolates between data points. It finds values of a one-dimensional function underlying the data at intermediate points.
Interpolation is the same operation as table lookup .
All the interpolation methods require that x be monotonic. The 'cubic' method also requires that x contain uniformly spaced points. Here are two vectors representing the census years from 1900 to 1990 and the corresponding United States population in millions of people. Now interpolate within the data at every year from 1900 to 2000, and plot the result. Sometimes it is more convenient to think of interpolation in table lookup terms where the data are stored in a single table.