Thanks Duncan - a couple of extra points... I should have perhaps pointed
out that the data are on a *regular*
'box' grid (with each value currently spaced at 1 degree intervals). Also,
I'm looking for something
fairly simple, like a bilinear interpolation (where each new point is
created based on the values of the
four points surrounding it).
In answer to your question, JanAv is simply the data frame of values.
And yes, you're right, I think I'll need
a 2D interpolation as it's a grid with latitude and longitude values
(which as an aside, I guess these need
to be interpolated differently? In a 1D format??). I think you're also
right in that the 'akima' package
isn't suitable for this job, as it's designed for irregular grids.