Thread Subject: Interpolation wind speed

Hi,

I have got the data for several wind measuring stations containing latitude, longitude and wind speed data series (x,y,z).
x(lat) y(lon) z(speed)
67.55 3.22 12.2
                     12.5
                     14.2
and so on...

Now I want to interpolate the wind speed from the 2 or 3 closest wind measuring stations to the latitude and longitude of a wind farm to get the wind speed used to calculate the power production. The problem is that neither the coordinates of the measuring stations nor the ones for the wind farms are equaly distrubuted so the normal interpolation (interp2) is not working. Has anybody got an idea how I can solve this problem?

Thanks in advance!

On 21 Jan, 14:33, "Tobias " <tobias.aig...@elkraft.ntnu.no> wrote:
> Hi,
>
> I have got the data for several wind measuring stations containing latitude, longitude and wind speed data series (x,y,z).
> x(lat)   y(lon)   z(speed)
> 67.55   3.22    12.2
>                      12.5
>                      14.2
> and so on...
>
> Now I want to interpolate the wind speed from the 2 or 3 closest wind measuring stations to the latitude and longitude of a wind farm to get the wind speed used to calculate the power production. The problem is that neither the coordinates of the measuring stations nor the ones for the wind farms are equaly distrubuted so the normal interpolation (interp2) is not working.  Has anybody got an idea how I can solve this problem?

The idea is straight-forward:

1) Triangulate the (lat,long) positions
2) Plot a triangulated surface of wind vs position
3) Pick the interpolated wind data as the height
   of the surface at the desired positions

The implementation might be cumbersome, though.
If you already know 3 measurements that surround the
desired position, use the same algorithm with the
known data. It's simple geometry, deriving the equation
for a plane from the coordinates of three points known
to be in the plane. You did that kind of thing in High
School or thereabouts.

Rune

Hi Tobias,

doc griddata

Best regards,
Wolfgang

"Tobias " <tobias.aigner@elkraft.ntnu.no> wrote in message <hj9l2g$h4f$1@fred.mathworks.com>...
> Hi,
>
> I have got the data for several wind measuring stations containing latitude, longitude and wind speed data series (x,y,z).
> x(lat) y(lon) z(speed)
> 67.55 3.22 12.2
> 12.5
> 14.2
> and so on...
>
> Now I want to interpolate the wind speed from the 2 or 3 closest wind measuring stations to the latitude and longitude of a wind farm to get the wind speed used to calculate the power production. The problem is that neither the coordinates of the measuring stations nor the ones for the wind farms are equaly distrubuted so the normal interpolation (interp2) is not working. Has anybody got an idea how I can solve this problem?
>
> Thanks in advance!

"Tobias " <tobias.aigner@elkraft.ntnu.no> wrote in message <hj9l2g$h4f$1@fred.mathworks.com>...
> Hi,
>
> I have got the data for several wind measuring stations containing latitude, longitude and wind speed data series (x,y,z).
> x(lat) y(lon) z(speed)
> 67.55 3.22 12.2
> 12.5
> 14.2
> and so on...
>
> Now I want to interpolate the wind speed from the 2 or 3 closest wind measuring stations to the latitude and longitude of a wind farm to get the wind speed used to calculate the power production. The problem is that neither the coordinates of the measuring stations nor the ones for the wind farms are equaly distrubuted so the normal interpolation (interp2) is not working. Has anybody got an idea how I can solve this problem?
>
> Thanks in advance!

http://www.advancedmcode.org/how-to-plot-a-coloured-surface-from-3d-scatter.html

http://www.advancedmcode.org/surface-recostruction-from-scattered-points-cloud-mycrustopen.html

http://www.advancedmcode.org/surface-recostruction-from-scattered-points-cloud-mycrust-robust.html



http://www.advancedmcode.org

Hi Tobias

I agree with the rest, best thing is to use:

If you have v = f(x,y,z):

- meshgrid: generate a grid in 3D 'xgrid, ygrid, zgrid' where you will evaluate the interpolation
- griddata3: interpolates the data to evaluate the function value 'v' on the new grid 'xgrid, ygrid, zgrid'

'doc griddata3' gives you a nice example in fact