introduction to matlab 2d 3d plots - numfactory.upc.edu · © numerical factory 2 plotting with...

© Numerical Factory

Numerical Methods in Engineering

Dept. Matemàtiques ETSEIB - UPC BarcelonaTech

Introduction to Matlab2D – 3D Plots

Prof. Toni Susín

© Numerical Factory 2

Plotting with Matlab

• 2D Plots:

– Plot

– Bar

– Polar,…

• 3D Plots:

– Mesh

– Surf,….

• Movies


2D Plots

h=pi/25;

x=0:h:2*pi;

y=sin(x);

plot (x, y);


2D Plots


2D Plots

h=pi/25;

x=0:h:2*pi;

y=sin(x);

z=cos(x);

plot(x,y,'gs',x,z,'ro');


2D Plots

• Plotting on a previous plot

hold on

line([0 2*pi],[0 0],'Color','m','LineWidth',2)


2D Plotsx=0:pi/25:2*pi;y=sin(x); z=cos(x);plot(x,y, 'g',x,z, 'r');legend('sin','cos');grid;title('Functions' );xlabel( ' x value ' );ylabel( ' y value ' );


2D Plotsx=0:pi/25:2*pi;y=sin(x); z=cos(x);plot(x,y,'g',x,z,'r');legend('sin','cos');grid;title('Functions' );xlabel( ' x value ' );ylabel( ' y value ' );

Axis values:axis([xmin,xmax,ymin,ymax])


2D PlotsFunction plots:

x=[0:0.2:10];

y=10*(1-exp(-x/3).*sin(10*x));

plot(x,y)

grid

title('Function Plot')



x=[0:0.2:10];

y=10*(1-exp(-x/3).*sin(10*x));

plot(x,y)

grid



2D PlotsInline Function:

x=[0:0.01:10];

f=@(x) 10*(1-exp(-x/3).*sin(10*x)); %inline function

y=f(x);

plot(x,y)

grid



2D PlotsInline Function:

x=[0:0.01:10];

f=@(x) 10*(1-exp(-x/3).*sin(10*x)); %inline function

myTitle= 'expSin Function';

myPlot(x,f,myTitle)

In an independent file named myPlot (as the function)

function myPlot(x,f,myTitle) y=f(x);

plot(x,y)

grid

title(myTitle)


2D Plots• Subwindows:

subplot(2,1,1), plot(x,y)

subplot(2,1,2), plot(x,z)


2D Plots

• Other 2D Matlab plots

bar pie area

stem polar stairs


2D Plots

• Getting mouse points:

[x y]=ginput(4);

plot(x,y,’g’);

fill(x,y,’r’);


2D Animation

• Animation

– Repeat a computation changing some parameter.

• Example:

sinusoide


% Sinusoid Animation: sin(x+P)% P phase value

%Assign values to the graphic windowfigNumber=figure('Name','Sinusoid Animation', 'NumberTitle','off', 'Visible','on');

endP=2*pi; %max variation angle for PincP=0.05; %increment de la Fasex=[-2*pi:0.2:2*pi]; %rang of x valuesfor P=-endP:incP:endP

y=sin(x+P);plot(x,y,'r')axis([-2*pi 2*pi -1.2 1.2])gridline([-2*pi 2*pi],[0 0],'Color','k','LineWidth',2)line([0 0],[-1.2 1.2],'Color','k','LineWidth',2)text(1.15,1.1,['Phase = ' num2str(P,'%.4f')])drawnow%pause(0.01)

end


% Sinusoide Animation: sin(x+P)% P phase value

%Assign values to the graphic windowfigNumber=figure('Name','Sinusoid Animation', 'NumberTitle','off', 'Visible','on');

endP=2*pi; %max variation angle for PincP=0.05; %increment de la Fasex=[-2*pi:0.2:2*pi]; %rang of x values

for P=-endP:incP:endPy=sin(x+P);plot(x,y,'r')axis([-2*pi 2*pi -1.2 1.2])gridline([-2*pi 2*pi],[0 0],'Color','k','LineWidth',2)line([0 0],[-1.2 1.2],'Color','k','LineWidth',2)text(1.15,1.1,['Phase = ' num2str(P,'%.4f')])drawnow%pause(0.01)

end

myVideo = VideoWriter('sinusoide.avi'); open(myVideo ); %open our video file

frame = getframe; writeVideo(myVideo,frame); %save to the video

close(myVideo);

Video Generation


3D Plots

• 3D- curves: Plot3 Function

fi=[0:pi/20:6*pi];

plot3(cos(fi),sin(fi),fi,’g’) %Helix curve


Helix Animation

% Helix Animationfi=[0:pi/20:6*pi];

for k=1:size(fi,2)plot3(cos(fi),sin(fi),fi,'g')hold on;plot3(cos(fi(k)), sin(fi(k)), fi(k),'marker','o',...

'markersize',8,'markerfacecolor', 'green');hold off;pause(0.1)

end


3D Plots

• 3D Surfaces: mesh, surf

x=[-8:0.4:8]; y=x;

[X,Y]=meshgrid(x,y);

R=sqrt(X.^2+Y.^2)+0.001;

W=sin(R)./R;

mesh(W)

surf(W)


3D Plots

>>contour(W)

>>waterfall(W)

>> meshc(W);


3D Plots

Exercise:

Generate

this screen


Sphere and Cylinder

[x,y,z]=sphere(20)

surf(x,y,z)

30


Sphere and Cylinder

[x,y,z]=cylinder([1,1], 20)

surf(x,y,z)

Cone?

31

introduction to matlab 2d 3d plots - numfactory.upc.edu · © numerical factory 2 plotting with...

Documents