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Optimal Interpolation ---HELP [message #2251]

Tue, 14 June 1994 13:25

k0c7289
Messages: 9
Registered: June 1994

Junior Member

Hello,

Help!!!

I am looking for the subroutine of the optimal interpolation in time and space
which produces regular gridded data from the irrrgulary sampled data in
space and time. I am working with satellite sea surface
height track data.

Please send me a mail(cho@linkji.tamu.edu)
if you have information.

Thanks

K.CHO
TAMU

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Re: Optimal interpolation [message #31827 is a reply to message #2251]

Thu, 22 August 2002 12:46

Paul Van Delst[1]
Messages: 1157
Registered: April 2002

Senior Member

GB Karas wrote:
>
> oh well.. i think that really depends on your data
>
> i analyze MRI data, so I have to use sinc and windowed sinc
> interpolation

OT, but...

What is sinc (and windowed sinc) interpolation?

paulv

--
Paul van Delst
CIMSS @ NOAA/NCEP/EMC Beer is good.
Ph: (301)763-8000 x7274 My wife.
Fax:(301)763-8545

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Re: Optimal interpolation [message #31828 is a reply to message #2251]

Thu, 22 August 2002 12:07

jacobian
Messages: 4
Registered: August 2002

Junior Member

oh well.. i think that really depends on your data

i analyze MRI data, so I have to use sinc and windowed sinc
interpolation (which is NOT implemented in IDL), so i have to spawn
several times external programs for that purpose. After trying to
make some dlm's it just took too much time to glue them to IDL...
and eventually did not work.

I hope the next version will simplify DLM's a little bit.. :/
Or at least the Watsyn product will offer some decent registration
and interpolation algorithms. Anyone tried it?

cheers

Giorgos
Department of Radiology
Vrije Universiteit Medical Center
Amsterdam
The Netherlands

David Fanning <david@dfanning.com> wrote in message news:<MPG.17cdf92226117b93989971@news.frii.com>...
> trouble (the_cacc@hotmail.com) writes:
>
>> There's this great resource called The Internet that you may have
>> heard of? Try it, you'll like it!!!
>
> I think he was asking for IDL code. This would appear
> to be the appropriate place to ask the question, even
> *after* an exhaustive search of the Web. At least I
> know it is where I would have asked the question.
>
> Cheers,
>
> David

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Re: Optimal interpolation [message #31831 is a reply to message #2251]

Thu, 22 August 2002 08:49

Robert Stockwell
Messages: 74
Registered: October 2001

Member

Luis wrote:
> Hi,
>
> does somebody know abouts an optimal interpolation subrroutine. I am trying
> to compare some different interpolation techniques and this is the only one
> than I don't have programmed.
>
> thank you!
>
> ------------------------------------------------------------
> Luis Prieto Godino
> Dpto. Fï¿½sica de la Tierra II.
> U.C.M. Spain
> ------------------------------------------------------------
>
>

I've got some Loess fitting routines for 3D interpolation
of a two component vector field. It uses SVD to solve
the 3D second order polynomial fitting. These fitting parameters
are then used to interpolate the data. The Loess part is
a local fitting routine that weights the data based on
its distance from the required point. That weighting could
easily be modified to be based on some error measurement and
therefore become an optimal interpolation routine.
It also returns an estimate of the error of the value of
the interpolated point.

Does this sound like it would be useful?

It would take me a bit of work to bang it into a generalized
form. Also, my code for selecting the "near points" is a bit outdated
as it is based on 2 one dimensional histogram with return_index. That
part should be rewritten.

Cheers,
bob

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Re: Optimal interpolation [message #31836 is a reply to message #2251]

Thu, 22 August 2002 01:35

Luis
Messages: 2
Registered: August 2002

Junior Member

> There's this great resource called The Internet that you may have
> heard of? Try it, you'll like it!!!

I have been searching on the web and I don't have found a complete IDL
code for this technique. So I heve decided to post this question here. Any
help will be welcome.

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Re: Optimal interpolation [message #31845 is a reply to message #2251]

Wed, 21 August 2002 19:23

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

trouble (the_cacc@hotmail.com) writes:

> There's this great resource called The Internet that you may have
> heard of? Try it, you'll like it!!!

I think he was asking for IDL code. This would appear
to be the appropriate place to ask the question, even
*after* an exhaustive search of the Web. At least I
know it is where I would have asked the question.

Cheers,

David
--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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Re: Optimal interpolation [message #31846 is a reply to message #2251]

Wed, 21 August 2002 17:33

the_cacc
Messages: 104
Registered: October 2001

Senior Member

"Luis" <pgodino@eucmos.sim.ucm.es> wrote in message news:<ak02d9$bdq$1@crispin.sim.ucm.es>...
> Hi,
>
> does somebody know abouts an optimal interpolation subrroutine. I am trying
> to compare some different interpolation techniques and this is the only one
> than I don't have programmed.
>
> thank you!
>
> ------------------------------------------------------------
> Luis Prieto Godino
> Dpto. Fï¿½sica de la Tierra II.
> U.C.M. Spain
> ------------------------------------------------------------

There's this great resource called The Internet that you may have
heard of? Try it, you'll like it!!!

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Re: Optimal interpolation [message #31964 is a reply to message #31827]

Wed, 28 August 2002 09:25

jacobian
Messages: 4
Registered: August 2002

Junior Member

sinc interpolation relies on the following interpolating kernel:

sinc(x)=sin(x)/x

Paul van Delst <paul.vandelst@noaa.gov> wrote in message news:<3D653F9D.223EDD66@noaa.gov>...
> GB Karas wrote:
>>
>> oh well.. i think that really depends on your data
>>
>> i analyze MRI data, so I have to use sinc and windowed sinc
>> interpolation
>
> OT, but...
>
> What is sinc (and windowed sinc) interpolation?
>
> paulv

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