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2021-08-04-polar-chart.md

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descriptionnamedisplay_asorderpermalinkthumnail_githublayoutlanguagepage_typepublished
How to make Polar Charts plots in MATLAB<sup>&reg;</sup> with Plotly.
Polar Charts
scientific
16
matlab/polar-chart/
polar-chart.png
base
matlab
u-guide
false

Create Polar Plot

Plot a line in polar coordinates.

theta = 0:0.01:2*pi; rho = sin(2*theta).*cos(2*theta); polarplot(theta,rho) fig2plotly(gcf, 'TreatAs', 'polarplot');

Convert from Degrees to Radians Before Plotting

Create the data to plot.

theta = linspace(0,360,50); rho = 0.005*theta/10;

Convert the values in theta from degrees to radians. Then, plot the data in polar coordinates.

theta = linspace(0,360,50); rho = 0.005*theta/10; theta_radians = deg2rad(theta); polarplot(theta_radians,rho) fig2plotly(gcf, 'TreatAs', 'polarplot');

Plot Multiple Lines in Polar Coordinates

Plot two lines in polar coordinates. Use a dashed line for the second line.

theta = linspace(0,6*pi); rho1 = theta/10; polarplot(theta,rho1) rho2 = theta/12; hold on polarplot(theta,rho2,'--') hold off fig2plotly(gcf, 'TreatAs', 'polarplot');

Plot Radius Values at Equally Spaced Angles

Specify only the radius values, without specifying the angle values. polarplot plots the radius values at equally spaced angles that span from 0 to 2π. Display a circle marker at each data point.

rho = 10:5:70; polarplot(rho,'-o') fig2plotly(gcf, 'TreatAs', 'polarplot');

Plot Negative Radius Values

Create a polar plot using negative radius values. By default, polarplot reflects negative values through the origin.

theta = linspace(0,2*pi); rho = sin(theta); polarplot(theta,rho) fig2plotly(gcf, 'TreatAs', 'polarplot');

Change the limits of the r-axis so it ranges from -1 to 1.

theta = linspace(0,2*pi); rho = sin(theta); polarplot(theta,rho) rlim([-1 1]) fig2plotly(gcf, 'TreatAs', 'polarplot');

Specify Line Color for Polar Plot

Create a polar plot using a red line with circle markers.

theta = linspace(0,2*pi,25); rho = 2*theta; polarplot(theta,rho,'r-o') fig2plotly(gcf, 'TreatAs', 'polarplot');

Specify Line Color After Creation

Create a polar plot and return the chart line object.

theta = linspace(0,2*pi,25); rho = 2*theta; p = polarplot(theta,rho); fig2plotly(gcf, 'TreatAs', 'polarplot');

Change the line color and width and add markers.

theta = linspace(0,2*pi,25); rho = 2*theta; p = polarplot(theta,rho); p.Color = 'magenta'; p.Marker = 'square'; p.MarkerSize = 8; fig2plotly(gcf, 'TreatAs', 'polarplot');

Create Polar Plot with Complex Values

Plot complex values in polar coordinates. Display markers at each point without a line connecting them.

Z = [2+3i 2 -1+4i 3-4i 5+2i -4-2i -2+3i -2 -3i 3i-2i]; polarplot(Z,'*') fig2plotly(gcf, 'TreatAs', 'polarplot');

Ezopolar Plot of Mathematical Function

Plot the function 1+cos(t) over the domain [0,2π].

figure ezpolar('1+cos(t)') fig2plotly(gcf, 'TreatAs', 'ezpolar');

Create Scatter Chart

Create a scatter chart in polar coordinates.

th = pi/4:pi/4:2*pi; r = [19 6 12 18 16 11 15 15]; polarscatter(th,r) fig2plotly(gcf);

Use Filled Markers and Set Marker Size

Create a scatter chart that uses filled markers by specifying the optional input argument, 'filled'. Set the marker size to 75 points squared.

th = linspace(0,2*pi,20); r = rand(1,20); sz = 75; polarscatter(th,r,sz,'filled') fig2plotly(gcf);

Use Markers with Varying Sizes and Colors

Create a scatter chart with markers of varying sizes and colors. Specify the optional size and color input arguments as vectors. Use unique values in the color vector to specify the different colors you want. The values map to colors in the colormap.

th = pi/4:pi/4:2*pi; r = [19 6 12 18 16 11 15 15]; sz = 100*[6 15 20 3 15 3 6 40]; c = [1 2 2 2 1 1 2 1]; polarscatter(th,r,sz,c,'filled','MarkerFaceAlpha',.5) fig2plotly(gcf);

Convert from Degrees to Radians Before Plotting

Create data where the angle values are in degrees. Since polarscatter requires angle values in radians, convert the values to radians before plotting using deg2rad.

th = linspace(0,360,50); r = 0.005*th/10; th_radians = deg2rad(th); polarscatter(th_radians,r) fig2plotly(gcf);

Combine Two Scatter Charts

Combine two scatter charts in the same polar axes using the hold command. Add a legend with a description of each chart.

th = pi/6:pi/6:2*pi; r1 = rand(12,1); polarscatter(th,r1,'filled') hold on r2 = rand(12,1); polarscatter(th,r2,'filled') hold off legend('Series A','Series B') fig2plotly(gcf);

Modify Scatter Chart After Creation

Create a scatter chart and assign the scatter object to the variable ps.

th = pi/6:pi/6:2*pi; r = rand(12,1); ps = polarscatter(th,r,'filled'); fig2plotly(gcf);

Use ps to modify properties of the scatter object after it is created.

th = pi/6:pi/6:2*pi; r = rand(12,1); ps = polarscatter(th,r,'filled'); ps.Marker = 'square'; ps.SizeData = 200; ps.MarkerFaceColor = 'red'; ps.MarkerFaceAlpha = .5; fig2plotly(gcf);

Plot Random Bubbles

Define a set of bubble coordinates as the vectors th and r. Define sz as a vector of bubble sizes. Then create a bubble chart of these values.

th = linspace(0,2*pi,10); r = rand(1,10); sz = rand(1,10); polarbubblechart(th,r,sz); fig2plotly(gcf);

Specify Bubble Colors

Define a set of bubble coordinates as the vectors th and r. Define sz as a vector of bubble sizes. Then create a bubble chart and specify the color as red. By default, the bubbles are partially transparent.

th = 1:10; r = rand(1,10); sz = rand(1,10); polarbubblechart(th,r,sz,'red'); fig2plotly(gcf);

For a custom color, you can specify an RGB triplet or a hexadecimal color code. For example, the hexadecimal color code '#7031BB', specifies a shade of purple.

th = 1:10; r = rand(1,10); sz = rand(1,10); polarbubblechart(th,r,sz,'#7031BB'); fig2plotly(gcf);

You can also specify a different color for each bubble. For example, specify a vector to select colors from the figure's colormap.

th = 1:10; r = rand(1,10); sz = rand(1,10); c = 1:10; polarbubblechart(th,r,sz,c) fig2plotly(gcf);

Specify Bubble Transparency and Outline Color

Define a set of bubble coordinates as the vectors th and r. Define sz as a vector of bubble sizes. Then create a bubble chart. By default, the bubbles are 60% opaque, and the edges are completely opaque with the same color.

th = linspace(0,2*pi,10); r = rand(1,10); sz = rand(1,10); polarbubblechart(th,r,sz); fig2plotly(gcf);

You can customize the opacity and the outline color by setting the MarkerFaceAlpha and MarkerEdgeColor properties, respectively. One way to set a property is by specifying a name-value pair argument when you create the chart. For example, you can specify 20% opacity by setting the MarkerFaceAlpha value to 0.20.

th = linspace(0,2*pi,10); r = rand(1,10); sz = rand(1,10); bc = polarbubblechart(th,r,sz,'MarkerFaceAlpha',0.20); fig2plotly(gcf);

If you create the chart by calling the polarbubblechart function with a return argument, you can use the return argument to set properties on the chart after creating it. For example, you can change the outline color to purple.

th = linspace(0,2*pi,10); r = rand(1,10); sz = rand(1,10); bc = polarbubblechart(th,r,sz,'MarkerFaceAlpha',0.20); bc.MarkerEdgeColor = [0.5 0 0.5]; fig2plotly(gcf);

Add a Bubble Legend

Define a data set that shows the incoming air traffic at a certain airport over a certain period of time.

  • Define theta as a vector of angles of approach for the incoming planes.
  • Define altitude as a vector of altitudes.
  • Define planesize as a vector of plane sizes, measured in the number of passengers. Then display the data in a bubble chart with a bubble legend that shows the relationship between the bubble sizes and the number of passengers on the planes.
theta = repmat([0 pi/2 7*pi/6],1,4) + 0.25*randn(1,12); altitude = randi([13000 43000],1,12); planesize = randi([75 500],[1 12]); polarbubblechart(theta,altitude,planesize) bubblelegend('Number of Passengers','Location','eastoutside') fig2plotly(gcf);

Display Bubbles in Different Axes on the Same Scale

Define two data sets showing the incoming air traffic at two different airports over a certian period of time.

  • Define theta1 and theta2 as vectors containing the angles of approach for the incoming planes.
  • Define planesize1 and planesize2 as a vectors of plane sizes, measured in the number of passengers.
  • Define altitude1 and altitude2 as vectors containing the altitudes for the planes.
theta1 = repmat([0 pi/2 7*pi/6],1,4) + 0.25*randn(1,12); theta2 = repmat([pi pi/6 3*pi/2],1,4) + 0.25*randn(1,12); planesize1 = randi([75 500],[1 12]); planesize2 = randi([1 50],[1 12]); altitude1 = randi([13000 43000],1,12); altitude2 = randi([13000 85000],1,12);

Create a tiled chart layout so you can visualize the data side-by-side. Then, create a polar axes object in the first tile, plot the data for the first airport, and add a title. Then repeat the process in the second tile for the second airport.

theta1 = repmat([0 pi/2 7*pi/6],1,4) + 0.25*randn(1,12); theta2 = repmat([pi pi/6 3*pi/2],1,4) + 0.25*randn(1,12); planesize1 = randi([75 500],[1 12]); planesize2 = randi([1 50],[1 12]); altitude1 = randi([13000 43000],1,12); altitude2 = randi([13000 85000],1,12); t = tiledlayout(1,2); pax1 = polaraxes(t); polarbubblechart(pax1,theta1,altitude1,planesize1) title('Airport A') pax2 = polaraxes(t); pax2.Layout.Tile = 2; polarbubblechart(pax2,theta2,altitude2,planesize2); title('Airport B') fig2plotly(gcf);

Reduce all the bubble sizes to make it easier to see all the bubbles. In this case, change the range of diameters to be between 5 and 20 points.

theta1 = repmat([0 pi/2 7*pi/6],1,4) + 0.25*randn(1,12); theta2 = repmat([pi pi/6 3*pi/2],1,4) + 0.25*randn(1,12); planesize1 = randi([75 500],[1 12]); planesize2 = randi([1 50],[1 12]); altitude1 = randi([13000 43000],1,12); altitude2 = randi([13000 85000],1,12); t = tiledlayout(1,2); pax1 = polaraxes(t); polarbubblechart(pax1,theta1,altitude1,planesize1) title('Airport A') pax2 = polaraxes(t); pax2.Layout.Tile = 2; polarbubblechart(pax2,theta2,altitude2,planesize2); title('Airport B') bubblesize(pax1,[5 20]) bubblesize(pax2,[5 20]) fig2plotly(gcf);

The planes at Airport A are generally much smaller than at Airport B, but the bubble sizes do not reflect this information in the preceding charts. This is because the smallest and largest bubbles map to the smallest and largest data points in each of the axes. To display the bubbles on the same scale, define a vector called allsizes that includes the plane sizes at both airports. Then use the bubblelim function to reset the scaling for both charts.

theta1 = repmat([0 pi/2 7*pi/6],1,4) + 0.25*randn(1,12); theta2 = repmat([pi pi/6 3*pi/2],1,4) + 0.25*randn(1,12); planesize1 = randi([75 500],[1 12]); planesize2 = randi([1 50],[1 12]); altitude1 = randi([13000 43000],1,12); altitude2 = randi([13000 85000],1,12); t = tiledlayout(1,2); pax1 = polaraxes(t); polarbubblechart(pax1,theta1,altitude1,planesize1) title('Airport A') pax2 = polaraxes(t); pax2.Layout.Tile = 2; polarbubblechart(pax2,theta2,altitude2,planesize2); title('Airport B') bubblesize(pax1,[5 20]) bubblesize(pax2,[5 20]) allsizes = [planesize1 planesize2]; newlims = [min(allsizes) max(allsizes)]; bubblelim(pax1,newlims) bubblelim(pax2,newlims) fig2plotly(gcf);
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