Thread Subject: Interpolare 2d on arbitrary points

Hello,

I have a little problem with interp2. It only accepts Meshgrids for X, Y, XI and YI. What my problem is:
I have Arbirtray points in 2d (x_i,y_i) with function values z_i and i would like to interpolate them to other points: (x1_i,y1_i). Those are on a sparse grid, so no meshgrid also.
Is there a command that can do this, or do I have to program a Spline Interpolation of some sort?

Thanks a lot

Philipp

"Philipp H" <saucool@gmx.de> wrote in message <h3hndq$rlu$1@fred.mathworks.com>...
> Hello,
>
> I have a little problem with interp2. It only accepts Meshgrids for X, Y, XI and YI. What my problem is:
> I have Arbirtray points in 2d (x_i,y_i) with function values z_i and i would like to interpolate them to other points: (x1_i,y1_i). Those are on a sparse grid, so no meshgrid also.
> Is there a command that can do this, or do I have to program a Spline Interpolation of some sort?

help griddata

John

"Philipp H" <saucool@gmx.de> wrote in message <h3hndq$rlu$1@fred.mathworks.com>...
> Hello,
>
> I have a little problem with interp2. It only accepts Meshgrids for X, Y, XI and YI. What my problem is:
> I have Arbirtray points in 2d (x_i,y_i) with function values z_i and i would like to interpolate them to other points: (x1_i,y1_i). Those are on a sparse grid, so no meshgrid also.
> Is there a command that can do this, or do I have to program a Spline Interpolation of some sort?
>
> Thanks a lot
>
> Philipp

Hi Philipp,

help griddata

or look for

http://www.mathworks.com/matlabcentral/fileexchange/8998

hth
kinor

Philipp,

If you have R2009a you should use the new scattered data interpolation class
TriScatteredInterp.
It is more robust than griddata and is also faster and more functional.
http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/ref/triscatteredinterp.html

Damian



"Philipp H" <saucool@gmx.de> wrote in message
news:h3hndq$rlu$1@fred.mathworks.com...
> Hello,
>
> I have a little problem with interp2. It only accepts Meshgrids for X, Y,
> XI and YI. What my problem is:
> I have Arbirtray points in 2d (x_i,y_i) with function values z_i and i
> would like to interpolate them to other points: (x1_i,y1_i). Those are on
> a sparse grid, so no meshgrid also.
> Is there a command that can do this, or do I have to program a Spline
> Interpolation of some sort?
>
> Thanks a lot
>
> Philipp