MATLAB: How to display contour data in polar coordinates onto a polar chart

MATLAB

I have angle and distance data (A*pi/180,R), where A is angle data in degrees and R is radial distance data between 0 and 10. At each of these points corresponds a magnitude Z. I have plotted contour data in cartesian coordinates with the angle A in the X-axis and the radial distance R in the Y-axis. I want to plot contours of Z onto a polar chart. However, when using POLAR in conjucntion woth CONTOUR, I do not get the right result.

Best Answer

The ability to display contour data in polar coordinates is not directly available in MATLAB.

However, the following code allows you to display contour data in polar coordinates onto a cartesian chart:

load PolarContourData;   % This file is attached.
h=polar([0 2*pi],[0 10]);delete(h);     %Create a polar axes and delete the line specified by POLAR
hold on;                                            
[theta, rho] = meshgrid(A*pi/180, R);
[X, Y] = pol2cart(theta, rho);
contour(X, Y,Z,4)                              %Create contour plots in polar coordinates onto polar chart 
set(gca,'visible','off');                       % Set the axes to invisible in order for hte polar patches to appear.

Related Solutions

MATLAB: How to create a contour plot in polar coordinates

A function that creates a polar contour plot is not present in MATLAB.

True polar axes are not supported in MATLAB. The POLAR function does the following to create a plot:

1. Accepts polar coordinates

2. Converts the data to Cartesian coordinates and plots them.

3. Draws the polar grid lines and text on a Cartesian axes system.

To create a contour plot in polar coordinates, you will need to follow a similar procedure. The following code shows an example:

% 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);

Next, you can produce the annotations using the POLAR function and create the contour plot:

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

Some of the annotations may be obscured when the contour plot is drawn. The most reliable way to work around this issue is to manually redraw them using the Plot Tools GUI or the ANNOTATION function.

MATLAB: Cartesian to polar cordinate’

use cart2pol function

Best Answer

Related Solutions

MATLAB: How to create a contour plot in polar coordinates

MATLAB: Cartesian to polar cordinate’

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