interp2 problem: input grid is not a valid meshgrid

I would like to interpolate, but I keep on getting the message: Error using interp2>makegriddedinterp (line 220) Input grid is not a valid MESHGRID.
Below is a simplified version of my data. Does anyone know how to solve this? Thank you!
Y=[30 29 27 20;32 31 29 22;35 34 32 25]
X=[0 2 5 10;0 2 5 10;0 2 5 10]
V=[1 2 3.5 4 ; 1.2 2.3 3.8 4.8; 1.4 2.6 4.2 5]
Yq=30
Xq=4

1 件のコメント

dpb
dpb 2014 年 6 月 13 日
編集済み: dpb 2014 年 6 月 13 日
Well, show what you did that raised the error and what you want. The round, translucent orb is somewhat murky today...
ADDENDUM
OK, I didn't look at the posted data closely enough first time -- from the doc for interp2 one finds--
... All the interpolation methods require that X and Y be monotonic and plaid (as if they were created using MESHGRID).
Your X data are monotonic ok, but they're not regular (plaid) as must be.

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回答 (1 件)

dpb
dpb 2014 年 6 月 13 日
編集済み: dpb 2014 年 6 月 13 日

3 投票

As noted in the comment, your data set doesn't meet the requirements of *interp2* of a uniform mesh in both directions. Use *TriScatteredInterp* instead...
>> F = TriScatteredInterp(X(:),Y(:),V(:));
>> F(Xq,Yq)
ans =
3.3444
>>

4 件のコメント

Matt J
Matt J 2014 年 6 月 13 日
編集済み: Matt J 2014 年 6 月 13 日
Or use scatteredInterpolant.
dpb
dpb 2014 年 6 月 13 日
>> which scatteredInterpolant
'scatteredInterpolant' not found.
>>
Matt J
Matt J 2014 年 6 月 13 日
編集済み: Matt J 2014 年 6 月 13 日
Time to upgrade! TriScatteredInterp will be removed eventually, see
dpb
dpb 2014 年 6 月 13 日
R2012b has brung my machine to about all it can do even after adding all the memory it can hold. Since I've retired from consulting, not much incentive to spend $$ on all the things I've become accustomed to besides Matlab so I'll probably just stand pat until the machine dies. Then it'll be a hard decision...

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2014 年 6 月 13 日

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