How do I plot a contour3 plot from polar cordinates?

I have a dataset such that the first column is the polar angle, second third fourth.... column is the magnitude of the polar coordinate at a different height.

For example, the first row would be all the magnitudes at angle 10 and every column would be the magnitude at a different height. the second row would be at 20 with the magnitude of the field at that angle and so on.

I am fairly new to matlab, but have some idea on how to get basic stuff done. I believe I might be doing something wrong with data array or coordinates. I get a polarplot from the data on excel with all the plots in the same axis, but I would like to get something like a contour3 plot to get an idea for a 3d image. The polar plot I am able to get from matlab is correct with all three layers on same axis (picture attached). I have also attached kinda what my data looks like. Any sort of help is greatly appreciated

Answer 1

[Star Strider]

I am not certain what your data are. Experiment with the pol2cart function to put your data in Cartesian coordinates (plotted as a polar plot) and then use those transformed data with the contour3 function.

[Uzair Khan]

I have attached a sample of kinda what my excel file looks like; I have been tinkering around with using meshgrid for x and y values(having the azimuth angles as my x value, and the magnitudes as my y values), and then using the contour3 function, but it may be that my understanding of how to implement the z value (aka, the height value) with the contour3 is not right.

[Star Strider]

Please post the file again. There are no data other than the angle. You can attach .csv, .xls, .xlsx and others.

[Uzair Khan]

heres a chunk of the file. Thanks a bunch bro

[Star Strider]

I cannot do much with your data.

See if this does what you want:

[D,S] = xlsread('Uzair Khan matlab.xlsx');

z = bsxfun(@plus, [1:3]*10, D(:,2:end));                    % Create ‘z’
[x, y, z] = pol2cart(D(:,1)*pi/180, D(:,2:end), z);

figure(1)
contourf(x, y, z)
axis equal

figure(2)
contour3(x, y, z)
grid on
axis equal

Also, you can attach your Excel files directly here. You do not have to ‘zip’ them first.

[Uzair Khan]

I think I have got it using your previous advise aswell, did a little knowledge brushup on axis and stuff. here is the code I used

 theta = t.*pi/180;   %t is the angle values from the table, found theta values
      %rho is also declared as columns 2,3,4
 %Declaring z
 A = [10 20 30];        %random numbers I used to decide height
 z = repmat(A,36,1);
 [X,Y,Z] = pol2cart(theta,rho,z);   %converting to cartesian
 contour3(X,Y,Z);      %finally found the contour plot
  end

I will give you code a try as well. Btw how we fill the gap between the layers with colors? Again, thanks a lot for your help

[Star Strider]

My pleasure.

The bsxfun function is more efficient than repmat, although the result will be the same.

If you want to ‘fill’ the space between the contours, use the surf function:

figure(3)
surf(X, Y, Z)
grid on
axis equal

[Uzair Khan]

I couldn't thank you enough man, it works perfectly (the code you gave as well). I wish well for your future! :)

[Star Strider]

As always, my pleasure!