[ncl-talk] Filter, filwgts_lanczos

[yang yang]

Hi Dennis:

Thanks for your help!

*In *filwgts_lanczos  a parameter, *fca* should be given. That is a scalar
indicating the cut-off frequency of the ideal high or low-pass filter: (0.0
< *fca* < 0.5). In a 1-D spatial data, I want to filter out small scale or
wavelength waves. For my case, I think that fca should be wavelength or
wave numbers, instead of frequency. Suppose I have 300 data with regular
100 m spatial interval. I would to remove wavelength smaller than 500
m. How to set fca to do the filtering? Thanks!

Regards
Ed

On Wed, Oct 28, 2015 at 10:20 AM, Dennis Shea <shea at ucar.edu> wrote:

> A filter has no idea whether the data is temporal or spatial. Most
> filters do assume constant spacing. If your spatial data is
> irregularly spaced, you will likely have to interpolate to equal
> spacing.
>
> On Tue, Oct 27, 2015 at 2:51 PM, yang yang <yang.yang816 at gmail.com> wrote:
> > Dear Sir/Madam:
> >
> > In NCL, examples of Filters using filwgts_lanczos  are only in temporal
> > domain. Now I want to do low-pass for my 1-D spatial data such as
> dropsonde
> > data or flight-track data. Does NCL have a similar function as
> > filwgts_lanczos to do the work for 1-D spatial data? or How to apply
> > filwgts_lanczos in a 1-D spatial data? Thanks!
> >
> > Regards
> > Ed
> >
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