matlab讲义9.ppt

1、Week 9,3D Plots 4D Plots Movies,The 3D version of plot is: plot3(x1,y1,z1,s1,x2,y2,z2,s2,),Three-dimensional Graphics,t = 0:pi/50:10*pi; plot3(sin(t),cos(t),t);,Curve plot in 3D,Surface Plot,X (resp. Y) is a matrix containing all the x-coordinates (resp. y) of the points on the grid, i.e. (X(i,j), Y

2、(i,j) is the coordinate of the (i,j)-th point in the grid.,compute Z at each coordinate in the mesh and plot,To plot, X,Y=meshgrid(-6 : 0.1 : 6, -6 : 0.1 : 6); R=sqrt(X.2+Y.2+.1); Z=sin(R)./R; mesh(X,Y,Z),The Mexican Hat, meshz(X,Y,Z) plot with zero plane, meshc(X,Y,Z) draws the underlying contours,

3、 surf(X,Y,Z) surface is filled with plates, surfnorm(X,Y,Z) plot normal vectors, shading interp; surface is shaded by interpolation, view(10,60); view from different angle, colormap(hot); surface is shaded with different color, colorbar bar gives height, contour(X,Y,Z,20) 20 contour lines, contour3(

4、X,Y,Z,20) 20 contour lines in 3D with correct height,How to generate a sphere? X,Y,Z=sphere(20); % sphere with 20 longitudes and 20 latitudes surf(X,Y,Z),How is it done in Matlab? First generate a rectangular grid of longitudes and latitudes n=20; long,lat = meshgrid(-pi: 2*pi/n :pi, -pi/2: pi/n :pi

5、/2);,X = cos(lat) .* cos(long); Y = cos(lat) .* sin(long);,These latitude and longitude values are then mapped to the X and Y spherical coordinates., Z = sin(lat); surf(X, Y, Z);,Using the X and Y spherical coordinates, we can compute the Z spherical coordinate, and plot the surface:,Four-dimensional Graphics,How to visualize 4D volume:,Cut the volume by planes. On each plane, illustrate the value of V by different colors,The Program:,Contour plots: contourslice(X,Y,Z,V,0,20) Plot 20 contour lines on the plane y=0,Isosurface plots: isosurface(X,Y,Z,V,1) Draw the surface where V=1,Movie,30 Fr