2-D bilinear data interpolation.
ZI = INTERP4(X,Y,Z,XI,YI) uses bilinear interpolation to
find ZI, the values of the underlying 2-D function in Z at the points
in matrices XI and YI. Matrices X and Y specify the points at which
the data Z is given. X and Y can also be vectors specifying the
abscissae for the matrix Z as for MESHGRID . In both cases, X
and Y must be equally spaced and monotonic.
Values of NaN are returned in ZI for values of XI and YI that are
outside of the range of X and Y.
If XI and YI are vectors, INTERP4 returns vector ZI containing
the interpolated values at the corresponding points (XI,YI).
ZI = INTERP4(Z,XI,YI) assumes X = 1:N and Y = 1:M, where
[M,N] = SIZE (Z).
F = INTERP4(Z,NTIMES) returns the matrix Z expanded by interleaving
bilinear interpolates between every element, working recursively
for NTIMES. INTERP4(Z) is the same as INTERP4(Z,1).
See also INTERP5 , INTERP3 .