MATLAB: Error with interp3 – please help

interp3?

I am trying to use interp3 on scatter data, and I'm getting the error:
Error using griddedInterpolant
The grid vectors are not strictly monotonic increasing.
Command:
[x,y,z] = meshgrid(0:0.25:1,0:0.25:1,0:0.25:2);
I3D=interp3(scatter(:,1),scatter(:,2),scatter(:,3),scatter(:,4),x,y,z,'linear');
Any idea what the issue is? I've done the same thing with 2D data using 'griddata', not sure why MATLAB is angry.
Thanks in advance!

Best Answer

Your scatter(:,1), scatter(:,2), scatter(:,3) each need to be in monotonic increasing order.
If you are attempting to interpolate a scattered set of values to a grid, you need to use one of the scattered interpolant routines, not a gridded interpolant line interp3()
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