Hi all,

I need to perform two-dimensional interpolation from nonrectangular grid to other nonrectangular grid. Would you help me with algorithm?

2 steps:

1. interpolate nonregular grid values to a regular grid

2. interpolate to get the other nonregular grid values from the regular grid

The simplest method is to just do bilinear interpolation from the first nonuniform grid onto the points in the second grid. The algebra is a bit tedious but straightforward. This method doesn't care if the second grid is uniform or not. However, things get much harder if you have special requirements, such as high accuracy, a function that is not smooth, or you need to match some constraint such as conserving mass when you interpolate a density field.

you can try least square in 2d. it can satisfy the accuracy's requirement