consulting 3D graph

Hi

I have a question about consulting a 3D graph design

I have in my data:

• Samples
• Frequency axis
• And the amplitude by sampling for freq

How would you present this data in a three-dimensional graph

Functions like surf are irrelevant because the Z axis does not depend on X&Y

Z is a known value

tnx :)

Example

[Rik]

What kind of plot do you want? A scatterplot?

[Bjorn Gustavsson]

What you have presented is data Z with size [32 x 7] at 7 frequencies and 32 "samples", in a plaid frequency-sample grid. For that surf is a reasonably suitable function to illustrate the data, as is pcolor (except for the fact that the last row and column disappears). You could also use scatter, (or plot3).

Unless you can explain why surf is "irrelevant".

[Shahar ben ezra]

First of all thanks for the help

I'm just not sure how to display the graph

In the SURF function I need to multiply the Z axis as a function of XY

for example

Z = sinx * exp (y)

In this case Z is a known value

Is a value I get directly from measuring instruments

I therefore consult how you would present a sub-dimensional surface to this data

[Rik]

You don't need to do that, it is just a way in which you can create some example data. You can just use the actual Z values.

[Shahar ben ezra]

this is work!!

tnx!!

Answer 1

[Cris LaPierre]

I think the natural choice here is a spectrogram. Samples go along one axis, frequency along the other, and color is used to convey power. Look at some of the examples on the linked page.

[Shahar ben ezra]

This is what I was looking for!

But I could not get a graph

Can you see where my error is?

[Cris LaPierre]

Could you copy/paste your code here? Use the CODE formatting option. You can attach your data using the paperclip icon as well.

[Shahar ben ezra]

%% 
clc, clear

my_date = readmatrix('3D PLOT');
vec_x_freq = my_date(1,2:end)
vec_y_samp = my_date(3:end,1)
matrix_z = (my_date(3:end,2:end))
figure(1)
spectrogram(vec_x_freq,vec_y_samp,matrix_z)

[Cris LaPierre]

Ok, so spectrogram is designed to take in the raw data and extract the frequency content. Your data appears to have already done that. So you really do just need a visualization method.

A simple 2D approach could be heatmap.

my_date = readmatrix("3D PLOT.xlsx");

vec_x_freq = my_date(1,2:end);
vec_y_samp = my_date(3:end,1);
matrix_z = (my_date(3:end,2:end));

figure
heatmap(matrix_z,"XDisplayLabels",vec_x_freq)
colormap parula

If you want a 3D plot, then surf would work, though your data doesn't make that a nice visualization.

figure
s=surf(matrix_z);
s.FaceColor = "interp";
colorbar

Another option might be a 3D bar chart.

figure
bar3(-matrix_z)
zlim([70 100])
xticklabels(vec_x_freq)
xlabel('Frequency')
ylabel('Sample')
zticklabels("-"+zticklabels);

[Cris LaPierre]

The best way to explore plotting options is to select the variable in your workspace, then open the Plots tab. All possible options for that variable will be displayed. Expand the list to see them all. Find one you like and select it.

[Shahar ben ezra]

Wow

you made my day

Thanks!