第六讲 Matlab绘图培训课件.ppt

* Instructor notes: Here we see our first example of fairly full featured 2D plot. In the slides that follow we will see how to go about arriving at a plot like this. The plot has a title that describes the dependent and independent variables. It has a label for the x-axis and for the y-axis. Each of these axis labels indicate what is being plotted with the corresponding units included in parentheses. The plot has major tick marks on each axis and the scale is such that an easily read step size occurs between each tick mark. Because there is more than one data set being plotted, there is a legend that indicates which curve corresponds to which data set. Note that the theoretical data is just a line, while the experimental data is a collection of data points that are connected by line segments. Data symbols should be used for measured data only, not for theoretical curves. Finally, there is a small text box that describes what is being plotted. * * * * * * stem3函数绘制离散序列数据的三维杆图，常用格式为： stem3(z) stem3(x,y,z) pie3函数绘制三维饼图，常用格式为： pie3(x) fill3函数等效于三维函数fill，可在三维空间内绘制出填充过的多边形，常用格式为： fill3(x,y,z,c) 例6-21 绘制三维图形： (1) 绘制魔方阵的三维条形图。 (2) 以三维杆图形式绘制曲线y=2sin(x)。 (3) 已知x=[2347,1827,2043,3025]，绘制饼图。 (4) 用随机的顶点坐标值画出五个黄色三角形。 程序如下： subplot(2,2,1); bar3(magic(4)) subplot(2,2,2); y=2*sin(0:pi/10:2*pi); stem3(y); subplot(2,2,3); pie3([2347,1827,2043,3025]); subplot(2,2,4); fill3(rand(3,5),rand(3,5),rand(3,5), y ) 例6-22 绘制多峰函数的瀑布图和等高线图。 程序如下： subplot(1,2,1); [X,Y,Z]=peaks(30); waterfall(X,Y,Z) xlabel(X-axis),ylabel(Y-axis),zlabel(Z-axis); subplot(1,2,2); contour3(X,Y,Z,12,k); %其中12代表高度的等级数 xlabel(X-axis),ylabel(Y-axis),zlabel(Z-axis); 符号表达式进行三维绘图 例6-23 绘制椭球面 ezmesh, ezsurf u=-2*pi:0.1:2*pi; v=-2*pi:0.1:2*pi; ezmesh(3*cos(u)*sin(v),2*cos(u)*cos(v),sin(u),[-2*pi,2*pi,-2*pi,2*pi]) 例6-24：绘制正螺面 u,v在-2pi至2pi 命令为ezsurf ezsurf(u*sin(v),u*cos(v),‘4*u,[-2*pi,2*pi,-2*pi,2*pi]) 例6-25：绘制圆锥面 u,v在-2pi至2pi 命令为ezsurf ezsurf(u*sin(v),u*cos(v),u,[-2*pi,2*pi,-2*pi,2*pi]) 6.5 图形修饰处理 6.5