- Invoke an initialization
procedure that
calculates the natural
neighbor relationships. This procedure is
NNPNTINITS in Fortran
and c_nnpntinits in C.
- Do the interpolation at the desired points. The procedure
for this is NNPNTS
in Fortran and c_nnpnts
in C.
- Terminate single point mode. This is done using the procedure NNPNTEND in Fortran and c_nnpntend in C.

See Example 6 for Fortran and C examples of interpolation in single point mode.

Due to implementation details, the values calculated in single point mode may differ slightly from values at the same coordinates when calculated using a grid.

If you have many datasets defined on the same input grid and need to interpolate at certain points in all datasets, then, in the interests of efficiency, you may want to retrieve the natural neighbors and weights for those points and calculate the interpolated vaules (sum of weights times function values) yourself. Depending on the language and precision you are using, one of the procedures NNGETWTS, NNGETWTSD, c_nngetwts, or c_nngetwtsd can be used for this. Example 10 illustrates how to do this.