Plotting selected columns of a matrix

I have a 32x1544 matrix.

I want to plot the 1st 8 column as plot1, 2nd 8 columns as plot2 and the 3rd 8 columns as plot3.

So all the 3 seperate plots are 32x8 2D-plot

Please advise. Thanks

Answer 1

[Star Strider]

I am not certain what you want as the result.

Try this:

M = rand(32,24) + (1:24);                       % Create Matrix
x = 1:32;                                       % Independent Variable Vector

figure
for k = 1:3
    subplot(3,1,k)
    plot(x, M(:,(1:8)+(k-1)*8))
    grid
end

Substitute your own matrix for ‘M’, and your independent variable vector for ‘x’.

[Farhan K]

Thanks. But what is this independent variable vector?

[Star Strider]

My pleasure.

The independent variable vector is usually the first argument to plot, although it is not absolutely necessary. I used it here to be certain that plot presents your matrix columns as you said you want them displayed, since it otherwise may not.

It does not change the plot results here, so you can just use:

plot(M(:,(1:8)+(k-1)*8))

They will be plotted the same way, regardless.

[Farhan K]

The plots need to be 2D dimentional. Maybe imagesc function should be used. Like the below 2D plot

[Star Strider]

I had no idea what you wanted with respect to your original Question. To me ’plot’ means a 2D plot such as what I wrote, unless otherwise specified. The imagesc plot would likely work.

Another option would be surf:

figure
surf(Z)
axis('tight')
view(0,90)

Note that the y-axis in surf is what you would normally expect, however it is reversed in image or imagesc plots.