EGR 106 Lecture 11 Three Dimensional Plotting

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EGR 106 Lecture 11Three Dimensional Plotting

• 3-D Line Plots
• Mesh and Surface Plots
• Special Plots
• View Command
• Textbook 9.1 9.4

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3-D Line Plots

• Recall 2-D plotting
• plot(x,y,line specifier,PropertyName,Propert
  yValue)
• Extend to 3-D
• plot3(x,y,z,line specifier,PropertyName,Prop
  ertyValue)

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3-D Line Plots - Example

• t00.16pi
• xsqrt(t).sin(2t)
• ysqrt(t).cos(2t)
• z0.5t
• plot3(x,y,z,'k','linewidth',1)
• grid on
• xlabel('x') ylabel('y') zlabel('z')

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Mesh and Surface Plots

• A function of two variables
• z f(x,y)
• can be represented graphically as a surface.
• First step
• Define a grid of x and y values

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Example -1? x ? 3, 1? y ? 4
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Matlab Command to Create Grid

• gtgt x -13
• gtgt y14
• gtgt X,Ymeshgrid(x,y)
• X
• -1 0 1 2 3
• -1 0 1 2 3
• -1 0 1 2 3
• -1 0 1 2 3
• Y
• 1 1 1 1 1
• 2 2 2 2 2
• 3 3 3 3 3
• 4 4 4 4 4

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Making Mesh and Surface Plots

• Example (Gilat text 2nd Editions Cover Figure)

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Mesh Plot
x-3.23 y-3.23 X,Ymeshgrid(x,y) Z1.8.
(-1.5sqrt(X.2Y.2)).cos(0.5Y).sin(X) mesh(X
,Y,Z) xlabel('x') ylabel('y')
zlabel('z') title('Mesh Plot')
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Mesh Plot mesh(X,Y,Z)
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Surface Plot surf (X,Y,Z)
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Mesh and Contour Plot meshc(X,Y,Z)
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Surface and Contour Plot surfc(X,Y,Z)
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Surface Plot with Lighting surfl(X,Y,Z)
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Waterfall Plot waterfall(X,Y,Z)
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2-D Contour Plot contour(X,Y,Z,25)
Number of contour lines
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3-D Contour Plot contour3(X,Y,Z,25)
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Filled Contour Plot contourf(X,Y,Z,25)
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Special Plots

• Sphere
• Cylinder
• 3-D Bar Plot
• 3-D Pie Chart

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Sphere Plot
X,Y,Zsphere(20) surf(X,Y,Z) xlabel('x')
ylabel('y') zlabel('z') axis square title('Plot
of a Sphere')
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Cylinder Plot
tlinspace(0,pi,20) r1sin(t) X,Y,Zcylinder(
r) surf(X,Y,Z) axis square title('Plot of a
Cylinder')
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3-D Bar Plot
Y1 6 7 2 6 7 3 5 7 4 5 7 3 4 7 2 3 6 1 2
7 bar3(Y) title('3D Bar Plot')
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3-D Pie Plot
X5 9 14 20 explode0 0 1 0 pie3(X,explode)
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The View Command
view(az,el) where az and el are angles given in
degrees
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View Command Example
x-3.23 y-3.23 X,Ymeshgrid(x,y) Z1.8.
(-1.5sqrt(X.2Y.2)).cos(0.5Y).sin(X) surf(X
,Y,Z) xlabel('x') ylabel('y') zlabel('z')
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View Command (cont.)
view(0,25)
view(30,25)
view(90,25)
view(60,25)
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View Command (cont.)
view(0,0)
view(90,90)