Rotating a 2 demential shape 30 degrees counter clockwise

Question

Shaan Ali 2016-7-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/297108-rotating-a-2-demential-shape-30-degrees-counter-clockwise

评论： Alex 2016-7-27

Hello. I am new to the Matlab community and I was having a bit of trouble rotating an irregular 2 dimensional shape. The coordinates a x = [0 0 2 2 0 -2 -2 0] and y = [0 2 2 3 5 3 1 0]. I have to rotate this 30 degrees counter clockwise on the same axis. Any suggestions? Thanks

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Alex 2016-7-26

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/297108-rotating-a-2-demential-shape-30-degrees-counter-clockwise#answer_229837

编辑：Alex 2016-7-26

This should rotate the points 30 degrees. R is using the rotation matrix to update the pairs of x,y coordinates.

z = [x; y];

thetad = 30;

R =[cosd(thetad) -sind(thetad); sind(thetad) cosd(thetad)];

for i = 1: 8

z(:,i) = R * z(:,i);

end

plot(z(1,:),z(2,:))

Here's another post that does it a little differently: http://www.mathworks.com/matlabcentral/answers/296860-rotating-a-2d-shape?s_tid=answers_rc1-1_p1

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Alex 2016-7-27

You can also use makehgtform to get the rotation matrix, which could be useful if you needed to perform more transformations on the matrix at once. Just make sure you convert your degrees to radians.

Example:

z = [x;y];

M = makehgtform('zrotate', (pi/6));

for i = 1:8

z(:,i) = M(1:2,1:2) * z(:,i);

end

plot(z(1,:),z(2,:))

Here's some more info for working with makehgtform: http://www.mathworks.com/help/matlab/ref/makehgtform.html

请先登录，再进行评论。