Hi, in the link you provide, an alaytical expression is evaluated on a given grid. Then, using the scatteredInterpolant function, a interpolation is computed. Finally, this interpolation is evaluated on a new grid. I think you can adapt this easily to your problem.

Thank you for all your answers. In the website I introduced previously I see a V function which was defined in some sample points. My current problem is that I don't have any information about the probable function I may define in sample points.

I would like to know how I can define a function formula like V or f(x,y)?

I would be grateful if you could kindly let me know your viewpoints about that also.

All the best,

Sahar

Right. I finally found the solution considering your guideline. Thank you very much.

Here is the result of my extrapolation. Although it is not as acceptable as I was thought but may be this is the best output I could get.

Yes. Exactly. The problem is that my data points are not available in the negative part of the curve. Since it was a mechanical limitation of my instrument.

However. I am thinking of another solution.

I have data points with lower resolution in the whole part of the curve. and the previous data was with higher resolution in only some parts.

I would like to merge these two surfaces together somehow I will have high resolution information in central part and lower resolution in data in the marginal parts. I would appreciate if you could let me know whether you have any viewpoint about that also or not?

Thank you for your consideration and time.

Here is a picture from my lower resolution data and the interpolated surface on it.

Right it was a quite good idea and worked very well.

Thank you for your comments and answers.