I want to interpolate 2d data. I have a function f(x, y) that is sampled as follows. For any y value in some array y_arr, I have the a set of points x_arr. Note that x_arr is different for any y, and even the boundaries of the x values are not the same. I would like to perform interpolation of this…

The README in Dierckx package seems to promise 2D interpolation on an irregular grid: https://github.com/kbarbary/Dierckx.jl

True. Though I am having problems with this package. Also, recently I saw that it is not actively maintained, so, therefore, I am looking for another solution.

You might try [image] GitHub - gher-uliege/DIVAnd.jl: DIVAnd performs an n-dimensional variational... DIVAnd performs an n-dimensional variational analysis of arbitrarily located observations - GitHub - gher-uliege/DIVAnd.jl: DIVAnd performs an n-dimensional variational analysis of arbit…

While Dierckx isn’t actively maintained, the existing features should work correctly, including 2D interpolation. New features may be slow to get added, that’s what the maintenance comment might have been about.

Thanks. I tried to use Dierckx and I get this error: No more knots can be added because the additional knot would (quasi) coincide with an old one: s too small or too large a weight to an inaccurate data point. The weighted least-squares spline corresponds to the current set of knots. I tried to…

[image] roi.holtzman: For 1d interpolations, I am using BSplineKit, but from its documentation, I could not understand if it is possible to use it for 2d. Multidimensional interpolations, using tensor product B-splines, have been in the plans for BSplineKit.jl for a while. There’s even a slig…

Thanks @jipolanco ! This code seems like it is designed for an even grid, isn’t it? I have a large set of x and y, and the values z(x,y). So this is an irregular grid. Is there a way to perform the 2d interpolation with the code you attached?

The example uses a regular grid, but it should work without a problem on irregular ones. (Just define xs and ys as vectors with sorted irregular values.)

[image] jipolanco: (Just define xs and ys as vectors with sorted irregular values.) But how can it be sorted? I essentially have a set (x_i, y_i) and the values z_i = z(x_i, y_i).

Maybe I misunderstood your initial post. If you have a curvilinear grid (your x_i coordinates vary with y), then I’m not sure I can help…

Interpolate 2d function

Specific Domains Numerics

rafael.guerra April 1, 2023, 3:31pm 12

Linking also this other thread, which contains examples of GMT.jl and DIVAnd.jl solutions.

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Interpolate 2d function

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