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From: omegayen on 26 Jul 2010 16:13
I am not sure how to properly do this.

I have several Fourier Transform 2d plots that I want to be able to show in 3D with essentially just the 2d plots stacked on top of each other.

Now what I have done thus far is take Fourier Transforms of some data I have in MATLAB and I have created a 262143 x 20 matrix, where each column represents a different Fourier Transform.

Now to plot this data in 2D space I would do

NValues=(1:262143)';
figure, plot(NValues,FTransform(:,1));

So in 3D I was thinking to do

X=ones(262143,20);
for ii=1:20
X(:,ii)=NValues;
end

and then this part I was not sure about

Y=0:3.814726369677503e-006:1;
Y=Y.';
for ii=1:20
Y(:,ii)=Y;
end
plot3(X,Y,abs(FTransform))

However this does not give me the 3D result of stacking each Fourier Transform as I ended. In this case the 3D plot is just a 2D plane. Can anyone help me understand what to do thanks.
From: Ross on 26 Jul 2010 19:41
"omegayen " <omegayen(a)ameritech.net> wrote in message <i2kq8v$iru$1(a)fred.mathworks.com>...
> I am not sure how to properly do this.
>
> I have several Fourier Transform 2d plots that I want to be able to show in 3D with essentially just the 2d plots stacked on top of each other.
>
> Now what I have done thus far is take Fourier Transforms of some data I have in MATLAB and I have created a 262143 x 20 matrix, where each column represents a different Fourier Transform.
>
> Now to plot this data in 2D space I would do
>
> NValues=(1:262143)';
> figure, plot(NValues,FTransform(:,1));
>
> So in 3D I was thinking to do
>
> X=ones(262143,20);
> for ii=1:20
> X(:,ii)=NValues;
> end
>
> and then this part I was not sure about
>
> Y=0:3.814726369677503e-006:1;
> Y=Y.';
> for ii=1:20
> Y(:,ii)=Y;
> end
> plot3(X,Y,abs(FTransform))
>
> However this does not give me the 3D result of stacking each Fourier Transform as I ended. In this case the 3D plot is just a 2D plane. Can anyone help me understand what to do thanks.

You need to arrange things so X has constant columns, but Y has constant rows (or perhaps vice versa): this is referred to in the Matlab help as "2-D plaid". The easiest way to do this is to use meshgrid to construct X and Y.

so xx needs to contain numbers 1 to 20 and yy needs to contain 0:3.814726369677503e-006:1 (or vice versa)

[X,Y]=meshgrid(xx,yy);
plot3(X,Y,F)
From: omegayen on 27 Jul 2010 12:59
"Ross " <rosswoodskiwi(a)hotmail.com> wrote in message <i2l6ek$ij2$1(a)fred.mathworks.com>...
> "omegayen " <omegayen(a)ameritech.net> wrote in message <i2kq8v$iru$1(a)fred.mathworks.com>...
> > I am not sure how to properly do this.
> >
> > I have several Fourier Transform 2d plots that I want to be able to show in 3D with essentially just the 2d plots stacked on top of each other.
> >
> > Now what I have done thus far is take Fourier Transforms of some data I have in MATLAB and I have created a 262143 x 20 matrix, where each column represents a different Fourier Transform.
> >
> > Now to plot this data in 2D space I would do
> >
> > NValues=(1:262143)';
> > figure, plot(NValues,FTransform(:,1));
> >
> > So in 3D I was thinking to do
> >
> > X=ones(262143,20);
> > for ii=1:20
> > X(:,ii)=NValues;
> > end
> >
> > and then this part I was not sure about
> >
> > Y=0:3.814726369677503e-006:1;
> > Y=Y.';
> > for ii=1:20
> > Y(:,ii)=Y;
> > end
> > plot3(X,Y,abs(FTransform))
> >
> > However this does not give me the 3D result of stacking each Fourier Transform as I ended. In this case the 3D plot is just a 2D plane. Can anyone help me understand what to do thanks.
>
> You need to arrange things so X has constant columns, but Y has constant rows (or perhaps vice versa): this is referred to in the Matlab help as "2-D plaid". The easiest way to do this is to use meshgrid to construct X and Y.
>
> so xx needs to contain numbers 1 to 20 and yy needs to contain 0:3.814726369677503e-006:1 (or vice versa)
>
> [X,Y]=meshgrid(xx,yy);
> plot3(X,Y,F)

great that helps. thanks!
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