Polar contour plot

Creates a contour plot from polar coordinates

Description

Have you ever wanted to do a contour plot of data in polar coordinates but didn't want to go through the hassle of converting it all to Cartesian coordinates? Well if so, here's your answer. A simple scriptlet that works exactly like MATLAB's built in contour plotting function. You can use clabel and handles just like contour. And if you don't like it, I'll give 100% of your money back (less S&H)

• MATLAB release: MATLAB 6.5 (R13)

[John D'Errico]

I could see that this might be a useful tool if you work with polar data.

What was good? Good help.

What could be far better?

- This code uses a double loop to do what ndgrid will do in one line. Loops are not bad in themselves, but then the author fails to pre-allocate the arrays that grow inside that loop. (Note that mlint points out this problem.)

- No error checks. When I tested this, I tried a few things, only to see empty figures. It turns out my z array was transposed. Yes, I found my error, but why not check a few sizes and tell the user what they did wrong?

- No H1 line, so lookfor will never find this code. Next year, when you are trying to remember the name of this function, lookfor won't be any help to you.

[Richard Rieber]

Made the changes that Mr. D'Errico recommended. Added an H1 line, error checks on array sizes, and preallocated memory before the nested for loops.

[eric meier]

awesome to find this handy code! thanks Richard.

[Alasdair Thom]

Lovely Stuff

[Sean]

Would be nice if there were a contour fill option.

[Dominique]

Sean
replace contour by countourf in the code, there are 3 instances, lines 52 54 and 56

Also, if you want 0 degree to be up and clockwise to be positive (wind and wave data for example) replace
line 45 and 46 by:
x(j,k) = -r(j)*cos(theta(k)+pi/2);
  y(j,k) = +r(j)*sin(theta(k)+pi/2);

Richard- Thank for the script. Very useful!, eventhough I did have to transpose Z compare to the function contour. Not a big deal.