Figure 2.
One-dimensional least-square fitting. The red solid circle is the projection point on the surface. The three inner grid points (connected with blue line) on the x-direction is used to fit the x-component at (x0, y, z). Similarly, the three inner grid points on the y-direction is used to fit the y-component at (x, y0, z). Note neither location of the fitted field components is a grid points but shares the x or y coordinate with the projection point, which is not a grid point in general. [Color figure can be viewed at wileyonlinelibrary.com]