Interpolation with three arrays

if true
  % code  
x = [0 .25 0 .5 .5 1 .5 .75];
y = [0 .25 .5 0 .5 .5 1 .75];
t = [20.99 25.74 29.7 22.34 40.48 45.75 63.01 62.98];
a = TriScatteredInterp(x(:),y(:),t(:),'nearest');
pnt1 = a(0,1)
end

I have these three arrays of data and I am trying to interpolate for the value of t for different values of x and y. for example t when x = 0 and y = 1. For some reason my code above is not working. Any help or ideas would be appreciated.

Answer 1

[Shashank Prasanna]

Why do you think this is not working? It seems to be working fine:

>> pnt1 = a(0,0)

pnt1 =

     20.9900

>> pnt1 = a(0,1)

pnt1 =

     63.0100

[tunny]

in the triscatteredinterp delete the 'nearest' because that just picks up the value in the array that is closest.

[Shashank Prasanna]

It appears that you are interested in extrapolation rather than interpolation.

TriScatteredInterp does not support extrapolation. However, the recent release of MATLAB R2013a, introduced scatteredInterpolant which does.

http://www.mathworks.com/help/matlab/math/scattered-data-extrapolation.html

You may have to upgrade to use this if you are on an older release.