how to do Polar plot?

Hi all,

Thank you for the help in advance. I wanted to plot the data usin' polar plot as the exmple shows https://matplotlib.org/examples/api/radar_chart.html

the vectors are attached as: theta=TSP rho=DNA trajectories= the direction of the wind

any help would be truly appreciated.

Answer 1

[Steven Lord]

If you want to create a polar plot, use the polarplot function introduced in release R2016a. It doesn't look exactly like the spider plot in the link Honglei posted, but it can look close, and it looks like some of the results in a Google Images search for "radar plot".

% Generate sample data
r = rand(1, 16);
th = linspace(0, 2*pi, length(r));

% Create the polar plot and get the handle to the axes
h = polarplot(th, r);
ax = ancestor(h, 'polaraxes');

% Use the axes handle to manipulate the ticks and tick labels
ax.ThetaTick = rad2deg(th);
ax.ThetaTickLabel = arrayfun(@(x) char(x+'A'), 0:15, 'UniformOutput', false);

I chose to use 'A' through 'O' as the tick labels because it was easy, but you could use a cell array containing your own names.

[Lilya]

Thank you so much for the help. But there is a small problem with the compass direction. it should follow the correct one, which is not like what i get (attached).

[Steven Lord]

I'm not completely sure what you mean by "should follow the correct one". Do you want 0 to be at the top rather than on the right? Change the ThetaZeroLocation property of the polaraxes.

ax = polaraxes;
ax.ThetaZeroLocation = 'top';

There are many other properties you can change to modify the appearance of the polaraxes.

For example, if you want a clock face, you can do so using four properties:

ax = polaraxes;
ax.ThetaZeroLocation = 'top';
ax.ThetaDir = 'clockwise';
ax.ThetaTickLabel = {'12'; '1'; '2'; '3';  '4';  '5'; ...
                      '6'; '7'; '8'; '9'; '10'; '11'};
ax.RTickLabel = {};

Technically you don't need to set ThetaZeroLocation and ThetaDir if you just reorder the ThetaTickLabel, but being able to start the clock labels with 12 (midnight) at the top of the clock face and have the clock labels occur in clockwise order just makes more sense to me.

[Lilya]

Great!! Thank you so much. it works.

Answer 2

[Honglei Chen]

There is an entry on File Exchange for radar plot

https://www.mathworks.com/matlabcentral/fileexchange/59561-spider--radar--plot

HTH

[Lilya]

Thank you. Honglei!, your help is appreciated.