contour plot in polar coordinates

 Hi

Found this code for generating contour plots with polar coordinates. It works, but I don't understand why and I also need to plot contour plots with polar coordinates. Can someone, please, explain the code to me?

Thanks

Shani

++++++++++THE CODE-----------------

% Create polar data

[r,t] = meshgrid(0:.1:5,0:pi/30:(2*pi));

z = r - t;

% Convert to Cartesian

x = r.*cos(t);

y = r.*sin(t);

h = polar(x,y);

hold on;

contourf(x,y,z);

% Hide the POLAR function data and leave annotations

set(h,'Visible','off')

% Turn off axes and set square aspect ratio

axis off

axis image

[Honglei Chen]

I think the comments are quite clear

[xiujuan wang]

Thank you very much.It helps me solve the problem.

Answer 1

[Kye Taylor]

It may be helpful to know that the line of code

z = r-t

defines the surface as a function of r and t. For example, if you just wanted to look at the function z(r) = r*cos(t), which is equivalent to the function f(x,y) = x in cartesian coordinates, change

 z = r - t;

to

 z = r.*cos(t);

[Shani Gal]

hi

i think z=r-t is part of the input. I have diffrent z for my r and t

what I Don't understand is how the combination of the function polar and contourf results in a conutuor plot in polar coordinates