Interpolating at a single point
Natgrid provides for interpolation at
a single point but, as indicated and documented in the
efficiency module, interpolation at
single points is very expensive and, in general, should be used
only for filling in a few missing data values.
For the same input dataset, in order to avoid having to calculate
the natural neighbor relationships every time interpolation is done
on a single point, interpolation at single points is implemented
as a three step process:
You can set any
you want before interpolating
at individual points, except
aspects cannot be calculated
while in single point mode.
- Invoke an initialization
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
- Terminate single point mode. This is done using the
procedure NNPNTEND in
c_nnpntend in C.
for Fortran and C examples of interpolation in single
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.