MATLAB: Plot wind directions and speed of a day with quiver

MATLAB and Simulink Student Suiteplotplottingquiverwind

I have given two vectors holding 24 hourly values for wind speed and direction.

I would like to use quiver to plot 24 arrows indicating speed and direction graphically.

I failed with my first tries:

clc; % Clear the command window.
close all; % Close all figures 
clear all; % Erase all existing variables.
workspace; % Make sure the workspace panel is showing.
% given vector of windspeeds througout a day (every h)
windspeeds = rand(1,24)
 % given vector of wind directions througout a day (every h)
 % the direction is noted in degrees ° from nord
 winddirections = randi([1 360],1,24)
 % create x/y grid 24x24 for one day
 [x,y] = meshgrid(1:24,1:24)
 % substract 90° to re-align north to the top
 u= mod(90 - winddirections, 360)
 v= mod(90 - winddirections, 360)
 % convert from degrees to fit the x/y matrix
 u=  cos(u) * pi/180
 v=  sin(u) * pi/180
 % put it on quiver
 quiver( cos(u) * pi/180, sin(u) * pi/180, x, y)

Current Result is

I do not yet know how to place these 24 arrows and how to calculate u,v to represent the direction at the given position (time of the day). The quiver doc is rather short. Any hints on how I could proceed.

Best Answer

workspace; % Make sure the workspace panel is showing.
% given vector of windspeeds througout a day (every h)
windspeeds = rand(1,24) ;
 % given vector of wind directions througout a day (every h)
 % the direction is noted in degrees ° from nord
 winddirections = randi([1 360],1,24) ;
 % create x/y grid 24x24 for one day
 [x,y] = meshgrid(1:24,1:24) ;
 % substract 90° to re-align north to the top
 u= mod(90 - winddirections, 360) ;
 v= mod(90 - winddirections, 360) ;
 % convert from degrees to fit the x/y matrix
 u=  cos(u) * pi/180 ;
 v=  sin(u) * pi/180 ;
 [U,V] = meshgrid(u,v) ;
 % put it on quiver
 quiver( x,y,U,V)

Related Solutions

MATLAB: Can someone help me with these 3D plots

you can plot these shapes in the following two ways(you can choose better way you like):

%%Seashell

[u, v] = meshgrid(linspace(0, 6 * pi, 100), linspace(0, 2 * pi, 100));
x = 2 * (1 - exp(u / (6 * pi))) .* cos(u) .* (cos(0.5 * v))^2;
y = 2 * (-1 + exp(u / (6 * pi))) .* sin(u) .* (cos(0.5 * v))^2;
z = 1 - exp(u / (3 * pi)) - sin(v) + exp(u / (6 * pi)) .* sin(v);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Seashell')
%%Eight torus

c = 1;
[u, v] = meshgrid(linspace(-pi, pi, 100));
x = cos(u) .* (c + sin(v) .* cos(u) - sin(2 * v) .* (sin(u) / 2));
y = sin(u) .* (c + sin(v) .* cos(u) - sin(2 * v) .* (sin(u) / 2));
z = sin(u) .* sin(v) + cos(u) .* (sin(2 * v) / 2);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Eight torus')
%%Helical spring

r1 = 0.25;
r2 = 0.25;
T = 2;
n = 6;
[u, v] = meshgrid(linspace(0, 2 * n * pi, 100), linspace(0, 2 * pi, 100));
x = (1 - r1 * cos(v)) .* cos(u);
y = (1 - r1 * cos(v)) .* sin(u);
z = r2 * (sin(v) + T * u / pi);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Helical spring')
%%Cornucopia

a = 0.3;
b = 0.5;
[u, v] = meshgrid(linspace(0, 2 * pi, 100), linspace(-3, 3, 100));
x = exp(b * v) .* cos(v) + exp(a * v) .* cos(u) .* cos(v);
y = exp(b * v) .* sin(v) + exp(a * v) .* cos(u) .* sin(v);
z = exp(a * v) .* sin(u);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Cornucopia')

Or alternatively you can also plot them using ezsurf as follows:

syms u v
%%Seashell
x = 2 * (1 - exp(u / (6 * pi))) * cos(u) * (cos(0.5 * v))^2;
y = 2 * (-1 + exp(u / (6 * pi))) * sin(u) * (cos(0.5 * v))^2;
z = 1 - exp(u / (3 * pi)) - sin(v) + exp(u / (6 * pi)) * sin(v);
figure, ezsurf(x, y, z)
%%Eight torus
c = 1;
x = cos(u) * (c + sin(v) * cos(u) - sin(2 * v) * (sin(u) / 2));
y = sin(u) * (c + sin(v) * cos(u) - sin(2 * v) * (sin(u) / 2));
z = sin(u) * sin(v) + cos(u) * (sin(2 * v) / 2);
figure, ezsurf(x, y, z)
%%Helical spring
r1 = 0.25;
r2 = 0.25;
T = 2;
n = 6;
x = (1 - r1 * cos(v)) .* cos(u);
y = (1 - r1 * cos(v)) .* sin(u);
z = r2 * (sin(v) + T * u / pi);
figure, ezsurf(x, y, z)
%%Cornucopia
a = 0.3;
b =0.5;
x = exp(b * v) .* cos(v) + exp(a * v) .* cos(u) .* cos(v);
y = exp(b * v) .* sin(v) + exp(a * v) .* cos(u) .* sin(v);
z = exp(a * v) .* sin(u);
figure, ezsurf(x, y, z)

I hope it helps. Good luck!

MATLAB: Hourly variation of wind for each month, using Quiver

This is my attempt with normalized/scaled arrows. See attachment.

load Viento_DMC
T=datetime(datevec(TIEMPO));
%%Velocity and direction
U=VV.*sind(DV);
V=VV.*cosd(DV);
Dir=atan2d(U,V);
TT=timetable(T,VV,Dir,U,V);
%%Take hourly mean (probably not necessary)
TT2=retime(TT,'hourly','mean');
%%Calculate hourly average per unique month/year (not sure if this is what you want, but easy to adjust)
[~,~,G]=unique([year(TT2.T) month(TT2.T) hour(TT2.T)],'rows');
VVm = splitapply(@nanmean,TT2.VV,G);
Um = splitapply(@nanmean,TT2.U,G);
Vm = splitapply(@nanmean,TT2.V,G);
VVm=reshape(VVm,24,numel(VVm)/24);
%%Normalize Um and Vm (UNCOMMENT TO NORMALIZE VECTORS)
for i=1:length(Um)
    Umn(i)=Um(i)./norm([Um(i) Vm(i)]);
    Vmn(i)=Vm(i)./norm([Um(i) Vm(i)]);
end
Um=Umn;
Vm=Vmn;
Um=reshape(Um,24,numel(Um)/24);
Vm=reshape(Vm,24,numel(Vm)/24);
%%create x/y grid 24x60
[x,y] = meshgrid(linspace(0,1,24),linspace(0,1,60)) ;
%%plot Wind speed and wind direction matrix's on xy grid with quiver
axis([0 1 0 1])
contourf(x,y,VVm');hold on
quiver(x,y,Um',Vm',0.5,'color','k')
axis([0 1 0.27 1])
%%Manipulate Labels
nLabelsY=10; %(60/nLabelsY must be integer NOT float)
[~,id,~]=unique([year(TT2.T) month(TT2.T)],'rows');
yticklabs=cellstr(datestr(TT2.T(id),'yyyy-mmm'))
set(gca,'ytick',linspace(0,1,nLabelsY),'yticklabels',{yticklabs{1:60/10:end}})
set(gca,'xtick',linspace(0,1,24),'xticklabels',sprintfc('%g',1:24))

Best Answer

Related Solutions

MATLAB: Can someone help me with these 3D plots

MATLAB: Hourly variation of wind for each month, using Quiver

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