radiusregion

Filled circular region (annulus) in polar coordinates

Since R2024a

Syntax

radiusregion(r1,r2)

radiusregion(R)

radiusregion(___,Name=Value)

radiusregion(pax,___)

pr = radiusregion(___)

Description

radiusregion(r1,r2) creates a filled circular region, or annulus, between the two specified radii in the current (polar) axes. To create one filled region, specify r1 and r2 as scalars. To create multiple filled regions, specify r1 and r2 as vectors of the same length.

radiusregion(R) specifies multiple regions as a matrix. To create n regions, specify R as a 2-by-n or n-by-2 matrix containing the inner and outer bounds for each region.

radiusregion(___,Name=Value) specifies properties for the region using one or more name-value arguments. If you create multiple regions, the property values apply to all of the regions. Specify the name-value arguments after all other inputs. For example, create a yellow radius region using radiusregion(5,10,FaceColor="yellow"). For a list of properties, see PolarRegion Properties.

radiusregion(pax,___) specifies the target polar axes for the filled region. Specify pax as the first argument in any of the previous syntaxes.

pr = radiusregion(___) returns one or more PolarRegion objects. Use pr to set properties of the filled regions after creating them. For a list of properties, see PolarRegion Properties.

Examples

Create Radius Region with Tick Labels in Radians

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 Multiple Radius Regions

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)

Customize Fill Color and Boundary Lines

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;

Match Radius Region Color to Plot Color

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;

Move Radius Region on Top of Plot

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";

Create Radius Regions in Different Axes

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")

Input Arguments

r1,r2 — Inner and outer radii

pair of scalars | pair of vectors

Inner and outer radii, specified as a pair of scalars or a pair of vectors. To create one filled region, specify r1 and r2 as scalars. To create multiple filled regions, specify vectors of equal length. You can specify the radius values in any order. Thus, radiusregion(1,5) and radiusregion(5,1) produce the same result.

To create an unbounded region, specify one of the radii as Inf. Specifying a value of –Inf creates a filled circle centered at r=0.

If any radii are NaN values, no region appears for those radii.

Example: radiusregion(0.5,1) creates a filled region from r=0.5 to r=1.

Example: radiusregion([1 3],[2 4]) creates two filled regions: one from r=1 to r=2 and the other from r=3 to r=4.

Data Types: single | double

R — Inner and outer radii for multiple regions

2-by-n matrix | n-by-2 matrix

Inner and outer radii for multiple regions, specified as a 2-by-n or n-by-2 matrix, where n is the number of regions. If you specify a 2-by-2 matrix, each column of the matrix corresponds to a region.

To create an unbounded region, specify one of the radii as Inf. Specifying a value of –Inf creates a filled circle centered at r=0.

If any radii are NaN values, no region appears for those radii.

Example: radiusregion([1 3; 2 4]) creates a filled region from r=1 to r=2, and another filled region from r=3 to r=4.

Data Types: single | double

pax — Target polar axes

PolarAxes object

Target polar axes for the filled region, specified as a PolarAxes object. Use this argument if you want to create the filled region in a specific PolarAxes object instead of the current axes.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: radiusregion(0.5,1,FaceColor="yellow") creates a yellow filled region.

Note

The properties listed here are only a subset. For a complete list, see PolarRegion Properties.

FaceColor — Fill color

[0.4902 0.4902 0.4902] (default) | RGB triplet | hexadecimal color code | "r" | "g" | "b" | ...

Fill color, specified as an RGB triplet, a hexadecimal color code, or a color name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7].

• A hexadecimal color code is a string scalar or character vector that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Therefore, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"
"none"	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB^® uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

EdgeColor — Boundary line color

"none" (default) | RGB triplet | hexadecimal color code | "r" | "g" | "b" | ...

Boundary line color, specified as an RGB triplet, a hexadecimal color code, or a color name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7].

• A hexadecimal color code is a string scalar or character vector that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Therefore, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"
"none"	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

FaceAlpha — Fill color transparency

0.3 (default) | scalar in range [0,1]

Fill color transparency, specified as a scalar in the range [0,1]. A value of 1 is opaque and 0 is completely transparent. Values between 0 and 1 are partially transparent.

LineStyle — Boundary line style

"-" (default) | "--" | ":" | "-." | "none"

Boundary line style, specified as one of the options listed in this table.

Line Style	Description	Resulting Line
"-"	Solid line
"--"	Dashed line
":"	Dotted line
"-."	Dash-dotted line
"none"	No line	No line

Version History

Introduced in R2024a