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Advanced Plotting
ผศ.ดร.อนั�นัต์ ผลเพิ่��มAnan Phonphoem
http://www.cpe.ku.ac.th/[email protected]
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Outline
xy plot Grid and Axis fplot polynomial plot subplot
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Plotting
Two-dimensional plot (xy plot) help graph2d
Three-dimensional plot (xyz plot, surface plot) help graph3d
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xy Plotting Functions
y = f(x) x-axis (abscissa) y-axis (ordinate)
abscissa
ordinate
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1 2 3 4 5 6 7 8 9 101000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
Distance (Km)
Cos
t (B
aht)
Cost of travelling
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The Anatomy of a PlotPlot Title
Y-Axis Label
X-Axis Label
Tick Mark
Tick-Mark Label
Legend Data Symbol
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Plot Essential Features
Axis label with unit Regular spaced tick mark (0.5, 1.0, 1.5,
…) More than one curve use Legend Use Title Plot measured data using Data Symbol Careful about connecting line
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Plotting example
y = 0.4 √1.8x for 0 ≤x ≤ 52 y = height of a rocket after launch (miles) x = horizontal (downrange) distance (miles)
>>x = [0:0.1:52];>>y = 0.4*sqrt(1.8*x);>>plot(x,y)>>xlabel(’Distance (miles)’)>>ylabel(’Height (miles)’)>>title(’Rocket Height as a Function of Downrange Distance’)
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Plotting example
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Grid and axis Commands
grid display gridlines toggle by grid on or grid off
axis override MATLAB axis syntax axis([xmin xmax ymin ymax])
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Plotting example II
>>x = [0:0.1:52];>>y = 0.4*sqrt(1.8*x);>>plot(x,y)>>xlabel(’Distance (miles)’)>>ylabel(’Height (miles)’)>>title(’Rocket Height as a Function of Downrange Distance’)
>>grid on>>axis([0 52 0 5])
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Plotting example II
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Plots of Complex Numbers
plot(y) plot(real(y),imag(y))
>>z = 0.1 + 0.9i;>>n = [0:0.01:10];>>plot(z.^n)>>xlabel(‘Real’), ylabel(‘Imaginary’)
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Plots of Complex Numbers
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fplot command
Automatically analyzes the function Then decides the plotting points Syntax fplot(‘string’,[xmin xmax])
string describe function [xmin xmax] value of variable
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fplot example
>>a_func = ‘cos(tax(x))-tan(sin(x))’;>>fplot(a_func,[1 2])>>xlabel(‘x’),ylabel(‘function’)>>title(‘using fplot’)
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fplot example I
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Compare to fplot
>>x=[1:0.01:2];>>y=cos(tax(x))-tan(sin(x));>>plot(x,y)>>xlabel(‘x’),ylabel(‘function’)>>title(‘using fplot’)
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Compare to fplot
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Compare to fplot
fplot plot
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Polynomial Plot
>>x=[-6:0.01:6];>>p=[3,2,-100,2,-7,90];>>plot(x,polyval(p,x))>>xlabel(‘x’),ylabel(‘p’)>>title(‘polynomial plot’)
p(x) = 3x5 + 2x4 – 100x3 +2x2 – 7x+90
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Polynomial Plot
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Subplots
Several smaller plots in one figure Syntax subplot(m,n,p)
m m rows n n columns p output plot
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Subplots example I
>>x = [0:0.01:5];>>y = exp(-1.2*x).*sin(10*x+5);>>subplot(1,2,1)>>plot(x,y),axis([0 5 -1 1])>>x = [-6:0.01:6];>>y = abs(x.^3-100);>>subplot(1,2,2)>>plot(x,y),axis([-6 6 0 350])
y = e-1.2x sin(10x + 5) for 0 ≤x ≤ 5y = |x3 - 100| for -6 ≤ x ≤ 6.
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Subplots example I
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Subplots example II
>>x = [0:0.01:5];>>y = exp(-1.2*x).*sin(10*x+5);>>subplot(2,1,1)>>plot(x,y),axis([0 5 -1 1])>>title(‘figure(a)’)>>x = [-6:0.01:6];>>y = abs(x.^3-100);>>subplot(2,2,2)>>plot(x,y),axis([-6 6 0 350])>>title(‘figure(b)’)
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Subplots example II