Figure Properties - SERC

interp2
spacing is handled by mapping the given values in X, Y, XI, and YI to an equally
spaced domain before interpolating. For faster interpolation when X and Y are
equally spaced and monotonic, use the methods '*linear', '*cubic',
'*spline', or '*nearest'.
ZI = interp2(...,method, extrapval) specificies a method and a scalar
value for ZI outside of the domain created by X and Y. Thus, ZI equals
extrapval for any value of YI or XI that is not spanned by Y or X respectively.
A method must be specified to use extrapval. The default method is 'linear'.
Remarks The interp2 command interpolates between data points. It finds values of a
two-dimensional function fxy ( , ) underlying the data at intermediate points.
f(x,y)
Interpolated points P(XI,YI,ZI)
Grid points P(X,Y,Z)
Interpolation is the same operation as table lookup. Described in table lookup
terms, the table is tab = [NaN,Y; X,Z] and interp2 looks up the elements of
XI in X, YI in Y, and, based upon their location, returns values ZI interpolated
within the elements of Z.
Examples Example 1. Interpolate the peaks function over a finer grid.
[X,Y] = meshgrid(-3:.25:3);
Z = peaks(X,Y);
[XI,YI] = meshgrid(-3:.125:3);
ZI = interp2(X,Y,Z,XI,YI);
mesh(X,Y,Z), hold, mesh(XI,YI,ZI+15)
hold off
axis([-3 3 -3 3 -5 20])
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