how i can draw a sector of a circle in matlab?

I want to draw a sector of a circle. The angle and the coordinate of sector's center are specified but the direction of the angle is random. i should mention that i need this pie to be a complete one, not just the curved part. like one of the pieces in this command:

pie([2 4 3 5],{'North','South','East','West'})

could anyone help me for the code please?

Answer 1

[Roger Stafford]

Let r be the circle's radius, P0 = [x0,y0] be its center, and theta be the required angle in radians.

   a1 = 2*pi*rand;  % A random direction
   a2 = a1 + theta;
   t = linspace(a1,a2);
   x = x0 + r*cos(t);
   y = y0 + r*sin(t);
   plot([x0,x,x0],[y0,y,y0],'y-')
   axis equal

[vatankhah]

great answer tanx alot,it works

[SaN AruL]

shows error Undefined function or variable 'theta'.

[Roger Stafford]

@SaN AruL: Look at the description of the problem, “Let r be the circle's radius, P0 = [x0,y0] be its center, and theta be the required angle in radians.” Theta, along with the radius, r, and the center P0 = [x0,y0] are assumed to be specified prior to the execution of the code. Theta is the assumed angle the circular sector.

Answer 2

[Adam]

I don't have time to give complete code and it isn't an area I have much expertise in, but the following example shows how you can plot a sector.

t = linspace(0,0.5*pi,128);

x = [0 cos(t) 0];
y = [0 sin(t) 0];

figure; patch( x, y, 'r' )

You can obviously change the range in t to suit start and end angles as you please and use the help to look further into patch or this blog post may provide some further help even though it heads off in a different direction:

http://blogs.mathworks.com/graphics/2014/12/04/tie-a-ribbon-round-it-parametric-curves-part-1/

Answer 3

[Hamidullah Riaz]

With a little manipulation:

x0=0;

y0=0;

theta=0.25*pi;

a1 = 2*pi*rand; % A random direction

r=100; % radius

a2 = a1 + theta;

t = linspace(a1,a2);

x = x0 + r*cos(t);

y = y0 + r*sin(t);

plot([x0,x,x0],[y0,y,y0],'y-')

axis equal