how to set different axis value?

Question

U B 2023-2-14

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1912485-how-to-set-different-axis-value

回答： Tiisetso Jeanet 2024-4-21

I want to change the axis display value in a contour plot.

   xylim = 0.0055 ;
   N = 5; x = linspace(-xylim,xylim,N); y = x; 
   [X,Y] = meshgrid(x,y);
  
    r = (X.^2 + Y.^2); rho = sqrt(r);
    f = 0.011 ; 
    theta = atan(rho./f) ;
    CPhi = X./rho; SPhi = Y./rho; 
     if mod(N,2) == 1
        CPhi((N-1)/2+1,(N-1)/2+1) = 1; 
        SPhi((N-1)/2+1,(N-1)/2+1) = 0; 
     end 
%% Function
    n1 = 1; 
    n2 = 1.5     ; 
    thetaI = theta;
    Th = theta*180/pi;
    thetaT = asin((n1./n2).*sin(thetaI));   
    CTi = cos(thetaI);
    CTt = cos(thetaT); 
    a = (n2.*CTi - n1.*CTt) ;      
    b = (n2.*CTi + n1.*CTt) ;
    c = (n1.*CTi - n2.*CTt) ;
    d = (n1.*CTi + n2.*CTt) ;
    Rp = a./b;
    Rs = c./d;
    
figure,contourf(X,Y,Rp,20);

Now the x and y axis has value -5 to +5 mm, from the below image we can see. I want to change the axis value from X and Y to the value of the red cross line of the Th value chart(below image) which is a function of X and Y. So new x axis should be [26.5651 14.0362 0 140362 26.5651} and new y axis [26.5651 14.0362 0 140362 26.5651}. can anyone help me please? Thank you.

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Answer 1

Kevin Holly 2023-2-14

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1912485-how-to-set-different-axis-value#answer_1171440

在 MATLAB Online 中打开

xylim = 0.0055 ;

N = 5; x = linspace(-xylim,xylim,N); y = x;

[X,Y] = meshgrid(x,y);

r = (X.^2 + Y.^2); rho = sqrt(r);

f = 0.011 ;

theta = atan(rho./f) ;

CPhi = X./rho; SPhi = Y./rho;

if mod(N,2) == 1

CPhi((N-1)/2+1,(N-1)/2+1) = 1;

SPhi((N-1)/2+1,(N-1)/2+1) = 0;

end

%% Function

n1 = 1;

n2 = 1.5 ;

thetaI = theta;

Th = theta*180/pi;

thetaT = asin((n1./n2).*sin(thetaI));

CTi = cos(thetaI);

CTt = cos(thetaT);

a = (n2.*CTi - n1.*CTt) ;

b = (n2.*CTi + n1.*CTt) ;

c = (n1.*CTi - n2.*CTt) ;

d = (n1.*CTi + n2.*CTt) ;

Rp = a./b;

Rs = c./d;

figure,contourf(X,Y,Rp,20);

h=gca;

% X Axis

h.XTick = [-0.0055,-0.0028,0,0.0028,0.0055];

newx = [26.5651 14.0362 0 140362 26.5651];

h.XAxis.TickLabels = {newx};

% Y Axis

h.YTick = [-0.0055,-0.0028,0,0.0028,0.0055];

newy = [26.5651 14.0362 0 140362 26.5651];

h.YAxis.TickLabels = {newx};

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Walter Roberson 2023-2-14

this is the changing labels option that I mentioned. As I noted it does not change coordinates for data tips. Or for ginput or similar.

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Answer 2

Walter Roberson 2023-2-14

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https://ww2.mathworks.cn/matlabcentral/answers/1912485-how-to-set-different-axis-value#answer_1171445

there are two different things you might mean.

If you want to change the actual x and y coordinates to the ones you indicated then you will have problems because your coordinates are not sorted and you would be warping the contour over an irregular surface. It could be done if strictly necessary, but it would take some work to transform the contour into something that could be warped over a surface.

But possibly you just want to change the x and y labels. You can do that by calling xtick and ytick and xlabel and ylabel routines. This would only change the decoration and would not for example affect datatips