Need a script to plot a circle with given radius and center

Question

Manu Manu 2014-3-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/121812-need-a-script-to-plot-a-circle-with-given-radius-and-center

评论： Image Analyst 2021-8-31

I need some help guys! Need a script to plot a circle with center(5,7) and radius 3. I have these:

clear clc
  r=3;
   t=0:pi/24:2*pi;
  x=r*cos(t);
  y=r*sin(t);
   plot(x,y,x,y)
   grid on

But only the radius works.. help please.

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

Image Analyst 2014-3-16

3
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/121812-need-a-script-to-plot-a-circle-with-given-radius-and-center#answer_128692

编辑：Image Analyst 2014-3-16

在 MATLAB Online 中打开

See the FAQ for code examples: http://matlab.wikia.com/wiki/FAQ#How_do_I_create_a_circle.3F

Here's one way from the FAQ that is most similar to yours:

xCenter = 5;
yCenter = 7;
theta = 0 : 0.01 : 2*pi;
radius = 3;
x = radius * cos(theta) + xCenter;
y = radius * sin(theta) + yCenter;
plot(x, y);
axis square;
xlim([0 10]);
ylim([0 12]);
grid on;
axis equal;

3 个评论
显示 1更早的评论隐藏 1更早的评论

picheri naveen 2021-8-31

Why we are taking theta = 0:0.01:2*pi

Image Analyst 2021-8-31

在 MATLAB Online 中打开

@picheri naveen You can choose whatever angle increment you want. If you want bigger angle increments, change 0.01 to 0.3 or whatever you want. Or if you want to specify the number of segments on the circle, you can use linspace():

startAngle = 0;
endAngle = 2 * pi;
numberOfSegments = 360; % Whatever you want.
theta = linspace(startAngle, endAngle,  numberOfSegments);

If the starting and ending angle are not 0 and 2*pi, then you'll get a partial circle (arc). And of course if your ending angle is more than 2*pi than your starting angle, you'll get some overlap.

The more you choose, the smoother the circle will be. Less will make it more polygon-like. For example if you had only 6 segments, it would look like a hexagon instead of a circle.

请先登录，再进行评论。

Answer 2

Image Analyst 2020-6-11

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/121812-need-a-script-to-plot-a-circle-with-given-radius-and-center#answer_449810

在 MATLAB Online 中打开

Here's another way

viscircles([5,7], 3);

2 个评论
显示无隐藏无

Tamara del Águila 2021-5-26

but which units does viscircle use? When I draw a circular roi with drawcircle, and then I plot in the obtained coordinates a circle with viscircle, the size do not match...

Image Analyst 2021-5-26

I believe they both use units of whatever the axes control is using. I think they should be the same. Post a small snippet of your code showing how you compute "size" and a screenshot showing the different circle sizes.

请先登录，再进行评论。