Re: splot pm3d and dgrid3d. Cannot understand the underlying details

In article <Xns9AE4AC10055276650A1FC0D7811DDBC81@[EMAIL PROTECTED]
>,
Rahul  <nospam@[EMAIL PROTECTED]
> wrote:
>
>Finally, I'm still mystified by the sentence in the docs that say:
>"The `dgrid3d` option is a simple low pass filter that converts scattered
> data to a grid data set."
>
>How is this low-pass-filtering? I apologize if I'm just not seeing 
>something that's obvious.

Think of each grid line as a Fourier transform of a slice of the data.
If you take enough Fourier terms, the grid line will be very 'ripply' and
pass through each relevant data point.  But if you take only a few
low-order terms (i.e. a low pass filter) then you get a smooth curve
that is an approximate fit to the data.

-- 
Ethan A Merritt