Re: moving average

• To: gaoming fu <gaoming_fu@xxxxxxxxxxx>
• Subject: Re: moving average
• From: Tom Whittaker <tomw@xxxxxxxxxxxxx>
• Date: Tue, 8 Jan 2002 14:35:56 -0600 (Central Standard Time)

The best definition I know of "moving average" is:

http://mathworld.wolfram.com/MovingAverage.html

In Meteorology, the "one pass Cressman" (which applies a distance-based,
non-linear weight to all observation points within a "circle of
influence") demonstrates this -- it is essentially an inverse
distance-weighted average of all the data points where the weight is > 0.
A more sophisticated extension was introduce by Barnes, and involves
multiple passes through the data (see Barnes 1994 article in Journal of
Atmos and Oceanic Technology).

tom

On Tue, 8 Jan 2002, gaoming fu wrote:

>
> Hello, All
>
> Recently some one told me that Moving average is another good way for
> interpolation. But I have no idea about it. Does VisAD suppor it?
>
> For example, for an area of 10 by 10 m, I have some irregular points (with x, 
> y,
> and z).
> Now I want to draw the surface using a grid with cell size of 1 m. First I 
> have to
> interpolate
> these grid points to get the z values (this can be easily done using
> WEIGHTED_AVERAGE
> and NEAREST_NEIGHBOR methods in VisAD), then draw those grid points. Now I 
> want to
> try the so called "Moving average" approach. The purpose is to get a smooth
> surface so that it is very close to the real topography visually.
>
> Any help will be highly apprecaited.
>
> Gaoming Fu
>
>
>
>
>
> _________________________________________________________________________________________
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>

--
Tom Whittaker
University of Wisconsin-Madison
Space Science and Eng. Center
ph:  608.262.2759

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