using surf and pol2cart on matrix

13 vues (au cours des 30 derniers jours)
prrrrr
prrrrr le 25 Juin 2020
Commenté : Star Strider le 26 Juin 2020
hello i have a 512x1000 matzrix
the coordinates are there divided into lines (x) as radius and columns (y) as angles. To each point in the matrix belongs a value (z).
How do I get the polar coordinates into cartesian coordinates (pol2cart). And can it plot at the end (with surf?)?
I would like to get in principle from my picture A the picture B
EDIT Forgot Code Example:
angles = (0:pi/8:2*pi)';
radii = 1:10;
[X, Y] = pol2cart(angles, radii)
  1 commentaire
Adam Danz
Adam Danz le 25 Juin 2020
Are the angles vector and the radii vector supposed to be different lengths?
How do those values plot a circle?

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Star Strider
Star Strider le 25 Juin 2020
Modifié(e) : Star Strider le 25 Juin 2020
The matrix you have is actually the ‘Z’ matrix. You need to create separate radius and angle matrices of the same size (use ndgrid or meshgrid for that, and be aware that their outputs are not the same), then use all three of those matrices as arguments to pol2cart. You will likely need to experiment a bit.
EDIT — (25 Jun 2020 at 23:17)
Using code example, try something like this:
Z = rand(512,1000); % Create 'Z'
angles = linspace(0, 2*pi, size(Z,2));
radii = linspace(1, 10, size(Z,1));
[A, R] = meshgrid(angles, radii);
[X, Y, Z] = pol2cart(A, R, Z);
figure
surf(X, Y, Z)
shading('interp')
grid on
.
  2 commentaires
prrrrr
prrrrr le 26 Juin 2020
Modifié(e) : prrrrr le 26 Juin 2020
thanks a lot :D
Star Strider
Star Strider le 26 Juin 2020
As always, my pleasure!

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