[SciPy-user] exact spline interpolation of an irregular dataset

Maik Troemel maik.troemel at maitro.net
Mon Nov 20 07:11:28 CST 2006


Hello again,

thank for your help. Now I've tested the delaunay package from the
sandbox, It works but there are some problems creating a convex hull of
the dataset. It seems to me as there are two hulls and not one. It looks
a little bit strange.

Probably I'm not alone with this problem. If someone is interested I can
send a picture of the result of the interpolation.

Is it possible that the spatial distribution of my input data is the
reason of the problem?

Greetings
Maik

> Hi Maik,
>
> On 07/11/06, Maik Trömel <maik.troemel@[...].net>  wrote:
>>  (again) i've got some problems concerning spline interpolation. I
want
>>  to interpolate a irregular data field. I've mapped this data field
on a
>>  2d-array.
>>  "iObj_spline_smooth =
>>  scipy.interpolate.fitpack2.SmoothBivariateSpline(x, y, v)"  works
fine.
>
>  Is there a posibility to make an exact interpolation?
>
> Yes, but not with the method used in BivariateSpline (exact
> interpolation requires the parameter s to be set to 0, but this will
> fail for the currently used method). If you have a regular grid then
> using RectBivariateSpline will work. As you haven't got a regular grid
> then I suggest you look at
>
>
http://www.scipy.org/Cookbook/Matplotlib/Gridding_irregularly_spaced_data
>
> which tells you how to do it with a package in the sandbox. We are
> currently working on improving this situation (within the next few
> weeks), so stay tuned.
>
> Best regards,
> John Travers



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