MATLAB: Rotation of a contour plot

aliasingimage processingimrotaterotation

I have a contour plot (Image1). I need to rotate it through a certain angle. If I save it as an image and then rotate it using transformation(or rotation) matrix, the whole plot including the axes are rotated(Image2). If I use imrotate for the matrix I have of the contour, the resultant contour doesn't actually rotate by the same angle which I specify (37 deg in the example, Image3) and more over sometimes the width of the plot decreases.
Can someone please help me overcome the problem. I want rotation of the contour plot without reducing the width and rotating exactly by the specified angle. Is it the aliasing effect?
Any help will be much appreciated. Many Thanks

Best Answer

Look at this example:
a = 37;
[x,y] = meshgrid(linspace(-4,4,30));
z = exp(-x.^2/15-y.^2);
contour(x,y,z)
xlim([-5 5])
ylim([-5 5])
x = x*cosd(a) - y*sind(a);
y = y*cosd(a) + x*sind(a);
figure
contour(x,y,z)
xlim([-5 5])
ylim([-5 5])
Is that what you want?
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