radiusregion

Create a polar plot and add a radius region that has an inner boundary of r=0.3 and an outer boundary of r=0.5.

% Create polar plot
theta = 0:0.01:2*pi;
rho = sin(2*theta).*cos(2*theta);
polarplot(theta,rho,LineWidth=1.5)

% Create filled region
r1 = 0.3;
r2 = 0.5;
radiusregion(r1,r2)

Change the theta-axis units to radians by setting the ThetaAxisUnits property.

pax = gca;
pax.ThetaAxisUnits = "radians";

Create three concentric filled regions by specifying the bounding radii as three-element vectors.

r1 = [0.2 0.5 0.8];
r2 = [0.4 0.7 1];
radiusregion(r1,r2)

Alternatively, specify one 2-by-3 matrix of radius values.

figure
R = [0.2 0.5 0.8; 0.4 0.7 1];
radiusregion(R)

You can specify PolarRegion properties, such as face color and boundary line width and color, by specifying one or more name-value arguments when you call radiusregion. Alternatively, you can set properties of the PolarRegion object after creating it.

For example, create two green radius regions. Specify an output argument to store the PolarRegion objects so that you can modify them later.

r1 = [0.2 0.8];
r2 = [0.4 1];
rr = radiusregion(r1,r2,FaceColor="g");

Change the color of the outer region to a shade of purple by specifying the FaceColor property as a hexadecimal color code. Then display thick boundary lines around the inner region by setting the EdgeColor property to a value other than "none" and setting the LineWidth property to 1.5.

% Set color of outer region
rr(2).FaceColor = "#5500FF";

% Set boundary color and line thickness
rr(1).EdgeColor = "b";
rr(1).LineWidth = 1.5;

Plot a blue and a red rose.

theta = linspace(0,2*pi,200);
rho1 = sin(2*theta).*cos(2*theta);
rho2 = 2*sin(2*theta).*cos(2*theta);

% Blue rose
rose1 = polarplot(theta,rho1,LineWidth=1.5);
hold on

% Red rose
rose2 = polarplot(theta,rho2,LineWidth=1.5);

Create radius regions that highlight the tips of the rose petals.

r1 = 0.4;
r2 = 0.5;
region1 = radiusregion(r1,r2);

r3 = 0.8;
r4 = 1;
region2 = radiusregion(r3,r4);

Match the color of each radius region to the corresponding rose by setting the SeriesIndex property of the region to the SeriesIndex property of the rose.

region1.SeriesIndex = rose1.SeriesIndex;
region2.SeriesIndex = rose2.SeriesIndex;

To move a radius region on top of a plot, set the Layer property of the PolarRegion object to "top". For example, plot a polar rose and add a radius region. When you create the radius region, specify a custom face color and transparency value so that you can see that the rose is on top of the radius region.

% Plot polar rose
theta = 0:0.01:2*pi;
rho = sin(2*theta).*cos(2*theta);
polarplot(theta,rho,LineWidth=1.5)

% Add radius region
r1 = 0.2;
r2 = 0.3;
rr = radiusregion(r1,r2,FaceColor=[0.8 0.8 0.8],FaceAlpha=0.7);

Move the radius region on top of the rose by setting the Layer property to "top".

rr.Layer = "top";

To create radius regions in different polar axes within the same figure, create a tiled chart layout. In this case, create two axes that each contain a radius region.

Use the tiledlayout function to create a 1-by-2 tiled chart layout t. Use the polaraxes function to create each PolarAxes object. By default, both objects occupy the first tile. Move the second PolarAxes object to the second tile by setting the Layout.Tile property.

t = tiledlayout(1,2);
pax1 = polaraxes(t);
pax2 = polaraxes(t);
pax2.Layout.Tile = 2;

Create a red radius region in the first polar axes, and create a green radius region in the second polar axes. Specify the PolarAxes object that you want to plot into as the first argument when you call radiusregion.

r1 = 0.2;
r2 = 0.6;
radiusregion(pax1,r1,r2,FaceColor="r")
radiusregion(pax2,r1,r2,FaceColor="g")