在matlabnbsp;画箭头

非常实用的文章

原文地址：在matlab 画箭头作者：纯情小郎君

完整见链接http://www.mathworks.com/matlabcentral/fx_files/14056/1/content/arrow3_examples.html

ARROW3 EXAMPLES (R13)

Two-dimensional Quiver Plots
- Example 1.
- Example 2.
- Example 3.
Three-Dimensional Quiver Plots
- Example 4.
- Example 5.
Cone Plots
- Example 6.
- Example 7.
Feather Plots
- Example 8.
- Example 9.
Compass Plots
- Example 10.
- Example 11.
Reference Frames
- Example 12.
- Example 13.
- Example 14.
Named Colors
- Example 15.
Update (Modify and Restore)
- Example 16.

Two-Dimensional Quiver Plots

Example 1. (cf. Joukowski Airfoil Transformation)

t=10*pi/180; u=0.1; v=0.1; r=1.1; tol=8e-2;

                    s=u+i*v; k=2*r*sin(t); w=exp(i*t);

                    [x,y]=meshgrid(-2.5:0.1:3.5,-3:0.1:3);

                    z=x+i*y; z(abs(z-s)<r-tol)=NaN;

                    f=w*z+exp(-i*t)*r^2./(z-s)+i*k*log(z);

                    a=0:0.1:2*pi; zc=r*(cos(a)+i*sin(a))+s;

                    c1=-1.5; c2=2.5; c3=c2-c1;

                    c=contour(x,y,imag(f),c1:c3/16:c2);

                    set(gca,'color',0.5*[1 1 1])

                    hold on, daspect([1 1 1])

                    fill(real(zc),imag(zc),'y'), colorbar

                    map=get(gcf,'colormap');

                    domain=0:1/(size(map,1)-1):1; m=1;

                    while m<length(c), n=m+c(2,m);

                    if c(2,m)>9, p=c(:,m+1:n)';

                        if p(end,1)>p(1,1), p=flipud(p); end

                        ndx=10:10:length(p);

                        p2=p(ndx,:); p1=p(ndx-3,:);

                        cc=interp1(domain,map,(c(1,m)-c1)/c3);

                        set(gca,'ColorOrder',cc)

                        arrow3(p1,p2,'0o',0.8)

                    end, m=n+1;

                    end, hold off

Example 1. Joukowski Airfoil Transformation

Example 2. (cf. Quiver)

[x,y]=meshgrid(-1:1/21:1);

                    z=x.*exp(-x.^2-y.^2);

                    [c,h]=contour(x,y,z);

                    set(h,'EdgeColor',0.45*[1 1 1])

                    ndx=1:3:length(x);

                    x=x(ndx,ndx); y=y(ndx,ndx); z=z(ndx,ndx);

                    [u,v]=gradient(z,1/7);

                    p1=[x(:),y(:)]; u=u(:); v=v(:);

                    m=abs(u+i*v); % gradient magnitude

                    daspect([1 1 1]), set(gca,'color',0.3*[1 1 1])

                    hold on, colormap hot, scale=0.4;

                    arrow3(p1,p1+scale*[u,v],'|',min(1.25*m,0.85))

                    hold off, h=colorbar;

                    set(h,'YTickLabel',num2str(str2num(get(h,...

                    'YTickLabel'))/scale))

Example 2. Surface Gradients

Example 3. (cf. Two-Dimensional Quiver Plots)

[x,y,z]=peaks(-2:0.05:2);

                    contour(x,y,z,10); h=gca;

                    ndx=1:4:length(x);

                    x=x(ndx,ndx); y=y(ndx,ndx); z=z(ndx,ndx);

                    [u,v]=gradient(z,0.2);

                    p1=[x(:),y(:)]; u=u(:); v=v(:);

                    m=abs(u+i*v); % gradient magnitude

                    hold on, daspect([1 1 1]), scale=0.025;

                    arrow3(p1,p1+scale*[u,v],'|',0.9*m/max(m))

                    hold off, title('Dual Colormap')

                    h1=colorbar; h2=copyobj(h1,gcf);

                    set(h,'color',0.4*[1 1 1],...

                    'position',get(h,'position')+[0.05 0 0 0])

                    % ----------------------------------------------------- Right Colorbar

                    p=get(h1,'position');

                    set(h1,'position',[0.87,p(2),0.05,p(4)],...

                    'YTickLabel',num2str(str2num(get(h1,...

                    'YTickLabel'))/scale))                               % freeze labels

                    map=colormap; cdata=reshape(map,size(map,1),1,3);

                    set(get(h1,'children'),'cdata',cdata)              % freeze colors

                    set(get(h1,'title'),'string','Gradient')

                    % ------------------------------------------------------ Left Colorbar

                    caxis auto, colorbar, colormap autumn

                    set(h2,'YAxisLocation','left',...

                    'position',[0.08,p(2),0.05,p(4)])

                    set(get(h2,'title'),'string','Contour')

Example 3. Dual Colormap

Three-Dimensional Quiver Plots

Example 4. (cf. Quiver3)

[x,y]=meshgrid(-2:0.25:2,-1:0.25:1);

                    z=x.*exp(-x.^2-y.^2);

                    surf(x,y,z,'EdgeColor','none')

                    axis([-2.5 2.5 -1.5 1.5 -1 1]), daspect([1 1 1])

                    set(gca,'CameraViewAngle',7)

                    [u,v,w]=surfnorm(x,y,z);

                    p1=[x(:),y(:),z(:)]; N=[u(:),v(:),w(:)];

                    hold on

                    arrow3(p1,p1+0.5*N,'1.5_b')

                    hold off, colormap spring

                    light('position',[-1 -1 -1],'style','local')

                    light('position',[0 1 1]), lighting gouraud

Example 4. Surface Normals

Example 5. (cf. Three-Dimensional Quiver Plots)

vx=2; vy=3; vz=10; a=-32; t=(0:.1:1)';

                    x=vx*t; y=vy*t; z=vz*t+1/2*a*t.^2;

                    r=[x,y,z]; v=gradient(r')';

                    axis([0 3 0 4 -10 2]), pbaspect([2 1 1])

                    hold on, grid on, view([70 18])

                    arrow3(r,r+v,'b',0.9)

                    hold off

Example 5. Velocity Vectors

Cone Plots

Example 6. (cf. Coneplot)

load wind, wind_speed=sqrt(u.^2+v.^2+w.^2);

                    xmin=min(x(:)); xmax=max(x(:));

                    ymin=min(y(:)); ymax=max(y(:));

                    zmin=min(z(:));

                    hsurfaces=slice(x,y,z,wind_speed,[xmin,xmax],ymax,zmin);

                    set(hsurfaces,'FaceColor','interp','EdgeColor','none',...

                                  'AmbientStrength',0.6)

                    hold on, daspect([2,2,1]), view(30,40), axis tight

                    xrange=linspace(xmin,xmax,8);

                    yrange=linspace(ymin,ymax,8);

                    [cx cy cz]=meshgrid(xrange,yrange,3:4:15);

                    ui=interp3(x,y,z,u,cx,cy,cz);

                    vi=interp3(x,y,z,v,cx,cy,cz);

                    wi=interp3(x,y,z,w,cx,cy,cz);

                    m=sqrt(ui.^2+vi.^2+wi.^2); m=m(:)/30;

                    p1=[cx(:),cy(:),cz(:)]; p2=[ui(:),vi(:),wi(:)];

                    hcones=arrow3(p1,p2,'r',m,3*m,'cone');

                    set(hcones,'DiffuseStrength',0.8)

                    hold off, axis off

                    camproj perspective, camzoom(1.2)

                    camlight right, lighting phong

Example 6. Wind Speed and Direction

Example 7. (cf. Vector Field Displayed with Cone Plots)

load wind, wind_speed=sqrt(u.^2+v.^2+w.^2);

                    hiso=patch(isosurface(x,y,z,wind_speed,40),...

                              'FaceColor','red','EdgeColor','none');

                    isonormals(x,y,z,wind_speed,hiso)

                    hcap=patch(isocaps(x,y,z,wind_speed,40),...

                              'FaceColor','interp','EdgeColor','none',...

                              'AmbientStrength',0.6);

                    hold on, colormap hsv, daspect([1,1,1]), view(65,45)

                    [f verts]=reducepatch(isosurface(x,y,z,wind_speed,30),0.07);

                    cx=verts(:,1); cy=verts(:,2); cz=verts(:,3);

                    ui=interp3(x,y,z,u,cx,cy,cz);

                    vi=interp3(x,y,z,v,cx,cy,cz);

                    wi=interp3(x,y,z,w,cx,cy,cz);

                    m=sqrt(ui.^2+vi.^2+wi.^2); m=m(:)/40;

                    p1=[cx(:),cy(:),cz(:)]; p2=[ui(:),vi(:),wi(:)];

                    h1=arrow3(p1,p2,'b',m,3*m,'cone');

                    xrange=linspace(min(x(:)),max(x(:)),10);

                    yrange=linspace(min(y(:)),max(y(:)),10);

                    [cx,cy,cz]=meshgrid(xrange,yrange,3:4:15);

                    ui=interp3(x,y,z,u,cx,cy,cz);

                    vi=interp3(x,y,z,v,cx,cy,cz);

                    wi=interp3(x,y,z,w,cx,cy,cz);

                    m=sqrt(ui.^2 + vi.^2 + wi.^2); m=m(:)/50;

                    p1=[cx(:),cy(:),cz(:)]; p2=[ui(:),vi(:),wi(:)];

                    h2=arrow3(p1,p2,'g',m,3*m,'cone');

                    hold off, axis tight, box on

                    set(gca,'xtick',[],'ytick',[],'ztick',[])

                    camproj perspective, camzoom(1.2)

                    camlight(-45,45), lighting phong

Example 7. Wind Speed and Direction

Feather Plots

Example 8. (cf. Feather)

theta=(-90:10:90)'*pi/180;

                    n=length(theta); p1=[1:n;zeros(1,n)]';

                    r=2*ones(n,1); [u,v]=pol2cart(theta,r);

                    plot([1 n],[0 0],'r')

                    axis([0 20 -2 2]), daspect([8 2 1])

                    hold on, grid on

                    arrow3(p1,p1+[u,v],'r',0.9)

                    hold off

Example 8. Feather Plot

Example 9. (cf. Plotting Complex Numbers)

t=(0:0.5:10)'; s=0.05+i; Z=exp(-s*t);

                    n=length(Z); p1=[1:n;zeros(1,n)]';

                    plot([1 n],[0 0],'b')

                    axis([0 22 -1 1]), daspect([8 1 1])

                    hold on, grid on

                    arrow3(p1,p1+[real(Z),imag(Z)],'b',0.8)

                    hold off

Example 9. Complex Number Plot

Compass Plots

Example 10. (cf. Compass Plots)

wdir =[45 90 90 45 360 335 360 270 335 270 335 335];

                    knots=[ 6 6 8 6   5   9   8   8   9 10 14 12];

                    [x,y]=pol2cart(wdir*pi/180,knots);

                    polar(0,15), axis(15.9*[-1 1 -1 1])

                    hold on

                    arrow3(zeros(length(x),2),[x',y'],'r',1.25)

                    hold off

Example 10. Wind Speed and Direction

Example 11. (cf. Compass)

Z=eig(randn(20)); m=abs(Z);

                    R=ceil(max(m)); r=R+0.3;

                    polar(0,R), axis(r*[-1 1 -1 1])

                    hold on

                    arrow3(zeros(length(Z),2),[real(Z),imag(Z)],'b',1.75*m/R)

                    hold off

Example 11. Complex Number Plot

Reference Frames

Example 12. Coordinate Axes

p=[4 2 1]; axis([-6 6 0 5 -1 1])

                    pbaspect([2 1.5 1]), view(55,15)

                    hold on

                    arrow3(repmat([p(1:2),0],4,1),...

                    [0 p(2) 0;p(1) 0 0;p;0 0 0],'--o',0,0,0.5)

                    arrow3(zeros(3),diag([7,5,1]),'o')

                    arrow3([0 0 0],p,'2.5s',1.5,[],0)

                    hold off, axis off, camlight left

                    set(gca,'CameraViewAngle',4)

                    text(7.1,0,0,'X'), text(0,5.05,0,'Y')

                    text(0,0,1,'Z','VerticalAlignment','bottom',...

                    'HorizontalAlignment','center')

Example 12. Coordinate Axes

Example 13. Eigenvectors

n=500; % generate test data

                    newz=[ 1 1 1]/sqrt(3);

                    newy=[ 0 -1 1]/sqrt(2);

                    newx=cross(newy,newz);

                    R=[newx;newy;newz]; % rotation matrix

                    U=randn(n,3)*diag([1,2,3])*R;

                    u=U(:,1)+10; v=U(:,2)+20; w=U(:,3)+30;

                    % plot eigenvectors with mean origin

                    plot3(u,v,w,'r.')

                    axis([0 20 10 29 20 40]), daspect([1 1 1])

                    view([-70,15]), set(gca,'CameraViewAngle',8)

                    hold on, grid on

                    mu=repmat(mean([u,v,w]),3,1);

                    [V,D]=eig(cov([u,v,w]));

                    p=9*V'+mu;

                    arrow3(mu,p,[],1.25,[],0)

                    p=p+ones(3);

                    text(p(1,1),p(1,2),p(1,3),'bfU')

                    text(p(2,1),p(2,2),p(2,3),'bfV')

                    text(p(3,1),p(3,2),p(3,3),'bfW')

                    hold off

Example 13. Eigenvectors

Example 14. (cf. Frenet)

z=(0:2/99:2)'; t=2*pi*z; r=2+z;

                    x=r.*cos(t); y=r.*sin(t);

                    R=[x,y,z]; dR=gradient(R')';

                    m=repmat(sqrt(sum(dR.*dR,2)),1,3);

                    T=dR./m; dT=gradient(T')';

                    m=repmat(sqrt(sum(dT.*dT,2)),1,3);

                    N=dT./m; B=cross(T,N);

                    plot3(x,y,z,'color',0.5*[1 1 1])

                    axis([-4 4 -4 4 0 2.5])

                    hold on, grid on, pbaspect([1 1 1])

                    set(gca,'CameraViewAngle',7)

                    plot3(0,0,0,'r'), plot3(0,0,0,'color',[0 0.5 0])

                    plot3(0,0,0,'b')

                    legend('Curve','Tangent','Normal','Binormal',2)

                    ndx=1:4:length(x); R=R(ndx,:);

                    arrow3(R,R+1.4*T(ndx,:),'r',0.9)

                    arrow3(R,R+1.4*N(ndx,:),'e',0.9)

                    arrow3(R,R+0.4*B(ndx,:),'b',0.9)

                    hold off, view(-50,5)

                    set(gcf,'renderer','zbuffer')

Example 14. Frenet Frames

Named Colors

Example 15. Named Color Table

arrow3('colors',0.4) % 24 named colors with 44 adjustable shades

Example 15. Named Color Table

Color Equivalencies

ColorOrder

Arrow3

Simulink

Arrow3

Color1

Blue

LightBlue

aZure

Color2

Evergreen

DarkGreen

Asparagus

Color3

Red

Orange

kumQuat

Color4

Sky blue

Gray

Light gray

Color5

Violet

Color6

Pear

Color7

Dark gray