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1、Matlab图形处理一、二维曲线的绘制语法：plot(x) %绘制以x轴为纵坐标二维曲线 plot(x,y) %绘制以x轴为横坐标、y为纵坐标的二维曲线1、用plot(x)绘图x1=1 2 3; %横坐标根据向量元素序号从1开始的向量plot(x1) x2=0 1 0plot(x2) x2 = 0 1 0 2、用plot(x,y)绘图x1=0:0.1:2*pi;y1=sin(x1);plot(x1,y1) x2=0 1 1 2 2 3;y2=1 1 0 0 1 1;plot(x2,y2)axis(0 4 0 2) 3、矩阵绘图x1=1 2 3;4 5 6 %以矩阵的每一列作图，横坐标为向量1:

2、2plot(x1) x1 = 1 2 3 4 5 6 x2=fix(randn(4,3)*2)plot(x2) x2 = -1 2 0 4 0 -2 0 0 1 0 -1 3 X=-1 2 3Y=1 2 3;4 5 6plot(X,Y) %X是向量，其长度与Y的列数相同，X与Y的每一行绘一曲线X = -1 2 3Y = 1 2 3 4 5 6 X1=1 2 3Y1=1 2;3 4;5 6plot(X1,Y1) %X1的长度与Y1的行数相同，X1与Y1的每一列绘一图X1 = 1 2 3Y1 = 1 2 3 4 5 6 X2=1 0;0 -1;1 2Y2=1 2;3 4;5 6plot(X2,Y2

3、) %如果X2，Y2均是矩阵，则它们的大小必须相同,矩阵X2的每一列和Y2的每一列绘一曲线X2 = 1 0 0 -1 1 2Y2 = 1 2 3 4 5 6 4、复向量绘图Z2=X2+i*Y2plot(Z2) %与plot(real(Z2),imag(Z2)相同Z2 = 1.0000 + 1.0000i 0 + 2.0000i 0 + 3.0000i -1.0000 + 4.0000i 1.0000 + 5.0000i 2.0000 + 6.0000i 5、用plot(x1,y1,x2,y2,.)绘制多条曲线x=0:0.1:2*pi;plot(x,sin(x),x,cos(x),x,sin(2

4、*x) 6、指定图形窗口语法：figure(n) % 指定第n个窗口,窗口名为Figure No.n,而不关闭其它窗口7、同一窗口绘制多个子图语法：subplot(m,n,k) %使mn幅子图中的第k幅成为当前图x=0:0.1:2*pi;subplot(2,2,1)plot(x,sin(x)subplot(2,2,2)plot(x,cos(x)subplot(2,2,3)plot(x,sin(2*x)subplot(2,2,4)plot(x,cos(3*x) 8、曲线的线型、颜色和数据点型(见书本p140表格)语法：plot(x,y,s) %s为类型说明的字符串参数，可以是线型，颜色和数据点型

5、之一或三种组合.clfx=0:0.1:2*pi;plot(x,sin(x),r-.)hold on %使当选前坐标系和图形保留plot(x,cos(x),b:o) 9、文字标注：包括图名(Title)、坐标轴(Lable)、文字注释(Text)和图例(Legend)语法：title(s) %图名 xlabel(s) % x坐标名 ylabel(s) % y坐标名 legend(s,pos) %在指定位置建立图例 legend off %擦除当前图中的图例 text(xt,yt,s) %在图形的(xt,yt)处注释注：pos可取值0 (自动取最佳位置) ，1(右上角，默认位置)， 2(左上角)，

6、 3(左下角)， 4(右下角)， -1(图右侧)，也可以直接在图中用鼠标将图例拖到满意位置.clear allclfx=0:0.1:2*pi;plot(x,sin(x)hold on plot(x,cos(x),ro) title(y1=sin(x),y2=cos(x)xlabel(x)legend(sin(x),cos(x),4) %在右下角添加图例text(pi,sin(pi),x=pi) 10、交互式图形命令语法：x，y=ginput(n) %用鼠标从图形上获取n个点坐标(x,y) gtext(s) %用鼠标把字符串放置到图形上x=0:0.1:2*pi;plot(x,sin(x)m,n=

7、ginput(2) %获取两点坐标gtext(2pi) %写2pim = 3.1532 6.1855n = -0.0029 -0.0029 二、三维图形的绘制1、三维曲线：语法：plot3(x,y,z,s) %x,y,z是同维向量时，绘制以元素为坐标的三维曲线，当x,y,z是同维的矩阵时，绘制三维曲线的条数等于矩阵的列数。s是指定线型、色彩、数据点型的字符串plot3(x1,y1,z1,s1,x2,y2,s2,.) %绘制多条曲线x=0:0.1:20*pi;plot3(x,sin(x),cos(x) t=(0:1000)/1000*10*pi;x=cos(t);y=sin(t);z=t;plo

8、t3(x,y,z) %绘制螺线 t=linspace(0,20*pi,501);plot3(t.*sin(t),t.*cos(t),t) t=linspace(0,20*pi,501);plot3(t.*sin(t),t.*cos(t),t,t.*sin(t),t.*cos(t),-t) 2、三维曲面语法：X,Y=meshgrid(x,y) %以向量x,y为基准，产生x-y平面的各栅格点坐标值矩阵mesh(z) %以矩阵的行下标作x轴,列下标作y轴,绘制网线图mesh(x,y,z,c) %c是用色矩阵，省略时c=z。绘制网线图surf(z) %绘制曲面图surf(x,y,z,c) %绘制曲面图

9、x=1 2 3 4;y=5 6 7;xx,yy=meshgrid(x,y) %绘网格点xx = 1 2 3 4 1 2 3 4 1 2 3 4yy = 5 5 5 5 6 6 6 6 7 7 7 7 x=linspace(-2,2,30);y=linspace(-2,2,25);xx,yy=meshgrid(x,y);zz=xx.*exp(-xx.2-yy.2);mesh(xx,yy,zz) t=0:0.1:2*pi;x=cos(t);y=sin(t);xx,yy=meshgrid(x,y);zz=xx.2+yy.2;mesh(xx,yy,zz) peaks z = 3*(1-x).2.*ex

10、p(-(x.2) - (y+1).2) . - 10*(x/5 - x.3 - y.5).*exp(-x.2-y.2) . - 1/3*exp(-(x+1).2 - y.2) x,y,z=peaks(50); plot3(x,y,z) r=1;x=-r:0.01:r;y=x;xx,yy=meshgrid(x,y);zz=sqrt(r2-xx.2-yy.2);surf(xx,yy,zz) 3、柱面和球面的绘制语法：x,y,z=cylinder(r,n) %绘制柱面，其中r为一向量，描述母线，表示单位高度里等分刻上定义的半径向量，n为柱面上分格线条数。x,y,z=sphere(n) %绘制球面，n

11、为分格线的条数r=1;cylinder(r,100) r=0:0.1:4;cylinder(r,100) t=2*pi:pi/12:5*pi;r=sin(t)+t; cylinder(r,100) plot(t,r) r=sin(t);cylinder(r,100) t=0:pi/12:3*pi;r=abs(exp(-0.25*t).*sin(t);X,Y,Z=cylinder(r,100);surf(X,Y,Z)colormap(1 0 0) plot(r) clear allt=0:0.1:2*pi;r=t.2;cylinder(r,10) sphere(100) 三、符号函数作图1、单独

12、变量符号函数作图语法：ezplot(Fx,xmin,xmax,ymin,ymax) %在指定x和y范围内，绘制y=f(x)的平面曲线ezplot(Fxy,xmin,xmax,ymin,ymax) %绘制f(x,y)=0的平面曲线ezplot(xt,yt,tmin,tmax) %绘制x=x(t),y=y(t)的平面曲线ezplot3(xt,yt,zt,tmin,tmax) %绘制x=x(t),y=y(t),z=z(t)三维曲线.syms t taoy=2/3*exp(-t/2)*cos(sqrt(3)/2*t);s=subs(int(y,t,0,tao),tao,t);subplot(2,1,1

13、)ezplot(y,0,4*pi)ylim(-0.2,0.7)grid onsubplot(2,1,2)ezplot(s,0,4*pi)grid ontitle(s=int_0t y(t)dt) 2、双独立变量函数作图ezsurf(Fxyz,dom_f) %在指定的矩形区域上画二元函数F(x,y,z)=0的曲面ezsurf(Fxyz,dom_f,circ) %在圆形域上画二元函数F(x,y,z)=0曲面ezsurf(x,y,z,dom_st,ngrid) %在指定矩形区域上画x=x(s,t),y=y(s,t) ,z=z(s,t)曲面ezsurf(x,y,z,dom_st,circ) %在指定圆

14、形域上画x=x(s,t),y=y(s,t) ,z=z(s,t)clfFxy=sin(x2+y);ezsurf(Fxy,-4,4,-6,6) x=cos(s)*cos(t);y=cos(s)*sin(t);z=sin(s);ezsurf(x,y,z,0,pi/2,0,3*pi/2)view(17,40)shading interpcolormap(spring)light(position,0,0,-10,style,local)light(position,-1,-0.5,2,style,local)material(0.5,0.5,0.5,10,0.3) 附录资料：matlab画二次曲面一、

15、螺旋线1.静态螺旋线a=0:0.1:20*pi;h=plot3(a.*cos(a),a.*sin(a),2.*a,b,linewidth,2);axis(-50,50,-50,50,0,150);grid onset(h,erasemode,none,markersize,22);xlabel(x轴);ylabel(y轴);zlabel(z轴);title(静态螺旋线); 2.动态螺旋线t=0:0.1:10*pi;i=1;h=plot3(sin(t(i),cos(t(i),t(i),*,erasemode,none);grid onaxis(-2 2 -2 2 0 35)for i=2:len

16、gth(t) set(h,xdata,sin(t(i),ydata,cos(t(i),zdata,t(i); drawnow pause(0.01)endtitle(动态螺旋线);(图略) 3.圆柱螺旋线t=0:0.1:10*pi;x=r.*cos(t);y=r.*sin(t);z=t;plot3(x,y,z,h,linewidth,2);grid onaxis(square)xlabel(x轴);ylabel(y轴);zlabel(z轴);title(圆柱螺旋线) 二、旋转抛物面b=0:0.2:2*pi;X,Y=meshgrid(-6:0.1:6);Z=(X.2+Y.2)./4;meshc(

17、X,Y,Z);axis(square)xlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;title(旋转抛物面)或直接用：ezsurfc(X.2+Y.2)./4) 三、椭圆柱面load clownezsurf(2*cos(u),4*sin(u),v,0,2*pi,0,2*pi)view(-105,40) %视角处理shading interp %灯光处理colormap(map) %颜色处理grid on %添加网格线axis equal %使x,y轴比例一致xlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;t

18、itle(椭圆柱面) %添加标题四、椭圆抛物面b=0:0.2:2*pi;X,Y=meshgrid(-6:0.1:6);Z=X.2./9+Y.2./4;meshc(X,Y,Z);axis(square)xlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;title(椭圆抛物面)或直接用：ezsurfc(X.2./9+Y.2./4)五、双叶双曲面ezsurf(8*tan(u)*cos(v),8.*tan(u)*sin(v),2.*sec(u),-pi./2,3*pi./2,0,2*pi)axis equalgrid onaxis squarexlabel(x

19、轴);ylabel(y轴);zlabel(z轴);shading flat;title(双叶双曲面)六、双曲柱面load clownezsurf(2*sec(u),2*tan(u),v,-pi/2,pi/2,-3*pi,3*pi)hold on %在原来的图上继续作图ezsurf(2*sec(u),2*tan(u),v,pi/2,3*pi/2,-3*pi,3*pi)colormap(map)shading interpview(-15,30)axis equalgrid onaxis equalxlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;titl

20、e(双曲柱面)七、双曲抛物面（马鞍面）X,Y=meshgrid(-7:0.1:7);Z=X.2./8-Y.2./6;meshc(X,Y,Z);view(85,20)axis(square)xlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;title(双曲抛物面)或直接用：ezsurfc(X.2./8-Y.2./6) 八、抛物柱面X,Y=meshgrid(-7:0.1:7);Z=Y.2./8;h=mesh(Z);rotate(h,1 0 1,180) %旋转处理%axis(-8,8,-8,8,-2,6);axis(square)xlabel(x轴);yl

21、abel(y轴);zlabel(z轴);shading flat;title(抛物柱面)或直接用：ezsurfc(Y.2./8) 九、环面ezmesh(5+2*cos(u)*cos(v),(5+2*cos(u)*sin(v),2*sin(u),0,2*pi,0,2*pi)axis equalgrid onxlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;title(环面)十、椭球ezsurfc(5*cos(u)*sin(v),(3*sin(u)*sin(v),4*cos(v),0,2*pi,0,2*pi)axis equalgrid onxlabel(

22、x轴);ylabel(y轴);zlabel(z轴);shading flat;title(椭球)十一、单叶双曲面ezsurf(4*sec(u)*cos(v),2.*sec(u)*sin(v),3.*tan(u),-pi./2,pi./2,0,2*pi)axis equalgrid onxlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;title(单叶双曲面)十二、旋转单叶双曲面load clownezsurf(8*sec(u)*cos(v),8.*sec(u)*sin(v),2.*tan(u),-pi./2,pi./2,0,2*pi)colormap(

23、map)view(-175,30)%alpha(.2) %透明处理axis equalgrid onaxis squarexlabel(x轴);ylabel(y轴);zlabel(z轴);shading flat;title(旋转单叶双曲面)十三、圆柱面subplot(1,2,1)ezsurf(2*cos(u),2*sin(u),v,0,2*pi,0,2*pi)grid onshading interpaxis equalxlabel(x轴);ylabel(y轴);zlabel(z轴);title(圆柱面)subplot(1,2,2)cylinder(30)shading interpaxis

24、 squaretitle(调用cylinder函数所得圆柱面)十四、二次锥面clc,clear;P=1,0,0; 0,cos(45*pi/180),sin(45*pi/180); 0,-sin(45*pi/180),cos(45*pi/180);for k2 = 1:31 for k1 = 1:31 x(k1,k2) = (k2-1)*cos ( (k1-1)*12*pi/180); y(k1,k2) = (k2-1)*sin ( (k1-1)*12*pi/180); z(k1,k2) = sqrt(x(k1,k2)2+y(k1,k2)2); Vxyz = P*x(k1,k2),y(k1,k2),z(k1,k2); x1(k1,k2)=Vxyz(1); y1(k1,k2)=Vxyz(2); z1(k1,k2)=Vxyz(3); endendsurf(x,y,z)hold on;surf(x1,y1,z1);shading flat;