How can I re-orient a polar scatter plot so zero is at the top?

The default orientation for a polarscatter plot is with the zero to the right hand side and 90 degrees at the top. I have geographical data (so zero degrees is north) and so I want the zero to be at the top and the numbers to increase clockwise. I've looked in all the axis properties but I can't see any way of doing this. I need to use a scatter plot because I want to colour code the markers. Is it possible to re-orient it?

Answer 1

[Star Strider]

Use polaraxes properties to do this —

th = rand(1,10)*2*pi;                                           % Angles
r = rand(size(th));                                             % Radii

figure
polarscatter(th, r, 75, 'filled')
title('Original')

figure
hps = polaraxes;                                                % First, Declare A 'polaraxes' Object & Return Its Handle
polarscatter(th, r, 75, 'filled');                              % Then Use 'polarscatter'
hps.ThetaZeroLocation = 'top';                                  % Change Angle Origin
hps.ThetaDir = 'clockwise';                                     % Change Angle Direction
title('Desired Result')

I am not certain when these properties were introduced. This works in R2021a.

.

[Helen]

The polaraxis properties aren't there in the earlier versions, but thank you.

[Steven Lord]

Which "earlier versions" are you using? ThetaZeroLocation and ThetaDir have been properties of polaraxes since at least release R2016a, which is the oldest documentation currently available on the website. They predate the introduction of polarscatter in release R2016b.

[Star Strider]

@Helen — My pleasure!

It always helps to post the Release/Version you’re using in the window provided for it. I assume the latest Release unless otherwise stated.

@Steven Lord — Thank you!

[Helen]

I'm using 2017b, but ThetaZeroLocation does not exist as a polarscatter property.

[Star Strider]

The ThetaZeroLocation property is not a polarscatter property. It is a polaraxes property. That is the reason I declared polaraxes first, then plotted onto it with polarscatter.

.

Answer 2

[Chunru]

th = linspace(0,2*pi,20);
r = rand(1,20);
sz = 75;
figure;
subplot(121)
polarscatter(th,r,sz,'filled')

subplot(122)
h = polarscatter(pi/2-th,r,sz,'filled');  % North, Clockwise
thetaTick = h.Parent.ThetaTick;
h.Parent.ThetaTickLabel = string(wrapTo360( 90-thetaTick));

[Helen]

Thank you. I was hoping that there was a way to do it that didn't involve manually fiddling with everything!