MATLAB: Polar-style direction plot

compassdegreesdirectionpolarwind

Hi guys

I have a wind-detector set up to monitor wind directions [angle=0-360 degrees] for a period of time, T. In order to visualize the wind direction over time I was considering making a polar-style plot in which the distance between the center and the circumference represents the time T and the wind-direction would be represented by a line navigating within the circle depending on time and angle.

How can I do this in matlab?

Thanks in advance!

Best Answer

doc quiver

quiver documentation

example

%create fake data to plot with quiver
a=360*rand(1,10); %create 10 angle values of the wind angle
s=10*rand(1,10);  %create 10 strength values of the wind 
u=s.*cosd(a);     %convert the angle to length of the arrow (x value) 
v=s.*sind(a);     %convert the angle to length of the arrow (y value) 
quiver(1:10,zeros(1,10),u,v) %do the quiver
axis([-1 12 -5 5])           %select the axes range so you can see it all

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MATLAB: Time series with quiver

See if this does what you want:

N = 10;
wind_vel = rand(N, 1)*25;                           % Velocitoy Vector
wind_dir = randi(360, N, 1);                        % Direction Vector
wind_u = cos(wind_dir).*wind_vel;                   % Wind ‘x’ Direction
wind_v = sin(wind_dir).*wind_vel;                   % Wind ‘y’ Direction
wind_w = zeros(N, 1);                               % Wind ‘z’ Direction
x = zeros(N, 1);                                    % Station Remains Stationary 

y = zeros(N, 1);                                    % Station Remains Stationary 
t = linspace(0, 25, N)';                            % Time
figure(1)
quiver3(x, y, t, wind_u, wind_v, wind_w)
hold on
plot3(x, y, t, '-k', 'LineWidth',2)
hold off
grid on

MATLAB: How to plot wind direction timeseries with arrows

The quiver() function is what you want to use. It's desiged exactly for this purpose.

Since your vectors are in degrees and the quiver function requires the x,y component vectors, use pol2cart() to convert your polar vectors to cartesian vectors. You'll also need to convert deg-->rad for the pol2cart inputs.

% WindDirection is the direction of wind (deg) 
% WindSpeed is the magnitude of the wind vector
[xWind, yWind] = pol2cart((pi/180).*WindDirection), WindSpeed); 
quiver(x, y, xWind, yWind)

Best Answer

Related Solutions

MATLAB: Time series with quiver

MATLAB: How to plot wind direction timeseries with arrows

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