# Mirror of countourf on X, Y axis

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ayoub on 7 Aug 2014
Commented: Sara on 7 Aug 2014
Hello everyone,
I'm working on 2d unsteady heat transfer modeling using Fortran. i have my results (temperature field) but only on 1/4 of my rectangel because i have (symetrical Boundary conditions).
I drew the results using matlab (countourf (x,y,z...), z=temperature, on 1/4 of the rectangle. can anyone of you explain me how to draw the temperature field on the entire rectangle ?? because it's symetrical, i would like to use mirror effect on x y axis. (-x-y) (-x+y) (x-y)
i don't wanna to multiply dimension of each vector *4, i tried it, it worked but very very slow.
there is my code : close all; clear;clc; a=load('new4.txt'); N=100
x=a(:,1); x coord y=a(:,2); y coord z=a(:,3);% temperature vetor
methode='v4'; Xmin = min(x); Xmax = max(x); Ymin = min(y); Ymax = max(y);
X =linspace(Xmin,Xmax,N); Y =linspace(Ymax,Ymin,N);
[X,Y] = meshgrid(X,Y);
Z = griddata(x,y,z,X,Y, methode); [c]=contourf(+X,+Y,Z,10); .

Sara on 7 Aug 2014
Look at the following example. If x and y start from 0, you can repeat the contour command 4 times. otherwise, you need to translate your coords.
x = 0:0.1:10;
y = -0:0.1:10;
[x,y]= meshgrid(x,y);
z = x.^2+y.^2;
figure
hold on
contourf(x,y,z)
contourf(-x,y,z)
contourf(x,-y,z)
contourf(-x,-y,z)
xlim([-10 10])
ylim([-10 10])
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Sara on 7 Aug 2014
set(gca,'layer','top');
grid on