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From: John D'Errico on 11 Aug 2010 16:30
"Richard " <REMOVETHISrcaldwellie(a)yahoo.com> wrote in message <i3ujjg$pfu$1(a)fred.mathworks.com>...
> Hi, I'm having difficulty with the interp1 command. Just don't get it! I've a set(actually very many sets) of values in an array with x and y coordinates 5. I want to interpolate and generate data with a resolution of 1. My data is of the form:
> 0 0 avalue
> 5 0 avalue
> 10 0 avalue
> .
> .
> 0 5 avalue
> 5 5 avalue
> 10 5 avalue
> 15 5 avalue
> avalue is an electric field strength and I need to generate the filed values at the points
> 1 0 newval
> 2 0 newval
> 3 0 newval
> 4 0 newval
> ..
> and so on
> How do I implement this with interp1

Think of it like this. Why would you use a ONE dimensional
interpolation tool to interpolate TWO dimensional data?

help interp2

John
From: Richard on 12 Aug 2010 04:44
"Matt J " <mattjacREMOVE(a)THISieee.spam> wrote in message <i3ur0b$k66$1(a)fred.mathworks.com>...
> "Richard " <REMOVETHISrcaldwellie(a)yahoo.com> wrote in message <i3uqku$r35$1(a)fred.mathworks.com>...
>
> > x y field_strength
> > where x and y are coordinates in 2d space. I have a 400metre X 400 metre area but only have data for every 5th point(i.e. 5 metre resolution)
> =================
>
> Like I said,
>
> interp2(0:5:400,0:5:400, field_strength, 0:400,0:400);

Thanks Matt. That worked, but i had to use meshgrid(0:400) for the XI and YI values. It just returned a vector otherwise
From: Matt J on 12 Aug 2010 10:16
"Richard " <REMOVETHISrcaldwellie(a)yahoo.com> wrote in message <i40c8n$235$1(a)fred.mathworks.com>...

> Thanks Matt. That worked, but i had to use meshgrid(0:400) for the XI and YI values. It just returned a vector otherwise
=================

No, you didn't have to use meshgrid, but the vector output was my fault. I should have written

interp2(0:5:400,0:5:400, field_strength, 0:400,(0:400).'); %Note transpose
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