How to get the matrix with the z values in cartesian coordinates from surface plot drawn in polar coordinates

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Mariia
Mariia 2018-4-23
回答： Mariia 2018-4-24
I have a surface initialized in cartesian coordinates and later converted to polar coordinates.
N = 100; % number of small sectors in one segmen
row = 10; % number of segments
M = N*row;
x = 0:(1-0)/(N-1):1; % segment matrix cartesian
xx = repmat(x,M,row);
radius = 0:(2*pi-0)/(M-1):2*pi;
radius = repmat(radius,M,1);
radius = transpose (radius);
alfa = 0:1/(M-1):1;
alfa = repmat(alfa,M,1);
[X,Y,value] = pol2cart(radius,alfa,xx);
figure
h = mesh(X,Y,value);
colormap gray;
view(2);
I plot it in polar coordinates.
Now I need to get the data points from this surface (z-values only) arranged as square matrix (the same size as plot area) exactly as they look in the plot. How can I get them?
Thanks in advance.
  2 个评论
Mariia
Mariia 2018-4-23

not exactly, for some reason "value" is identical to "xx" and contains the initial xx values

Here is what will happen if I plot value

figure
g =  surf(value, 'EdgeColor','none');
 colormap gray;
view(2);

I feel like I am missing something, because for cartesian coordinates X and Y values should be both positive and negative, and I have only positive...

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采纳的回答

Mariia
Mariia 2018-4-24
Okay, I made it work
N = 5; % N number of radiuses
M = 1000; % resolution in pixels
[X,Y] = meshgrid(0^2^2:2*N/(M-1):2*N);
[radius,alfa] = cart2pol(X,Y);
circle = sqrt((X-N).^2+(Y-N).^2);
circlef = fix(circle);
axicon = circle - circlef;
figure
h = mesh(X,Y,axicon);
colormap gray;
view(2);
axicon array gives what I need

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