Transcript Plotting - Citadel

Plotting
ELEC 206
Computer Applications for
Electrical Engineers
Dr. Ron Hayne
Two-Dimensional Plots
 x-y Plot

x-axis


independent variable
y-axis

dependent variable
x = [1:10];
y = [58.5, 63.6, 64.2, 67.3, 71.5, ...
88.3, 90.1, 90.6, 89.5, 90.4];
plot(x,y)
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Basic Plotting
 Labels
plot(x,y)
title('Lab 1')
xlabel('Voltage')
ylabel('Current')
grid on
plot(x,y), title('Lab 1'),
xlabel('Voltage'), ylabel('Current'),
grid on
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Basic Plotting
 Figure Control


pause, pause(n)
figure, figure(n)
 Multiple Plots

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
hold on, hold off
plot(X, Y, W, Z)
plotyy(X, Y, W, Z)
 Subplots

subplot(m,n,p)


m-by-n grid
pth window
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Basic Plotting
 Style Control
Line Type
solid
Indicator
-
dotted
Point Type
point
Indicator
.
Color
blue
Indicator
b
:
circle
o
green
g
dash-dot
-.
x-mark
x
red
r
dashed
--
plus
+
black
k
 Axis Scaling

axis, axis(v)

v = [xmin,xmax,ymin,ymax]
 Annotation

legend('string1', 'string2')
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Example
figure(3)
x = 0:pi/100:2*pi;
y1 = cos(4*x);
y2 = sin(x);
plot(x,y1,':r',x,y2,'--b')
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Other Plots
 Polar Plots

polar(theta,rho)
 Example
figure(4)
polar(x,y1,':r')
hold on
polar(x,y2,'--b')
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Other Plots
 Logarithmic Plots
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semilogx(x,y)
semilogy(x,y)
loglog(x,y)
 Bar Graphs and Pie Charts
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bar(x), barh(x)
bar3(x), bar3h(x)
pie(x), pie3(x)
 Histograms

hist(x), hist(x,bins)
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Problem Solving Applied
 UDF Engine Performance

Problem Statement


Calculate the velocity and acceleration using a script
M-file
Input/Output Description
Start Time = 0 sec
Velocity
Final Time = 120 sec
Acceleration
Time Increment = 10 sec
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Problem Solving Applied

Hand Example
velocity = 0.00001 time3 - 0.00488 time2 +
0.75795 time + 181.3566
 acceleration = 3 - 0.000062 velocity2
 For time = 100 sec

 velocity = 218.35 m/sec
 acceleration = 0.04404 m/sec2

Algorithm Development (outline)
Define time matrix
 Calculate velocity and acceleration
 Output results in table

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MATLAB Solution
clear, clc
%Example 4.3
%These commands generate velocity and acceleration
%values for a UDF aircraft test
%Define the time matrix
time = 0:10:120;
%Calculate the velocity matrix
velocity = 0.00001*time.^3 - 0.00488*time.^2 ...
+ 0.75795*time + 181.3566;
%Use calculated velocities to find the acceleration
acceleration = 3 - 6.2e-5*velocity.^2;
%Present the results in a table
[time', velocity', acceleration']
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Table Output
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Plotting Results
%Create x-y plots
plot(time,velocity)
title('Velocity of a UDF Aircraft')
xlabel('time, seconds')
ylabel('velocity, meters/sec')
grid on
%
figure(2)
plot(time, acceleration,':k')
title('Acceleration of a UDF Aircraft')
xlabel('time, seconds')
ylabel('acceleration, meters/sec^2')
grid on
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Plotting Results
%Use plotyy to create a scale on each side of plot
figure(3)
plotyy(time, velocity,time,acceleration)
title('UDF Aircraft Performance')
xlabel('time, seconds')
ylabel('velocity, meters/sec')
grid on
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Three-Dimensional Plotting
 3-D Line Plot

plot3(x,y,z)
 Surface Plots


mesh(z), mesh(x,y,z)
surf(z), mesh(x,y,z)

shading, colormap
 Contour Plots


contour(z), contour(x,y,z)
surfc(z), surfc(x,y,z)
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Example
figure(5)
z=peaks(25);
surfc(z)
colormap(jet)
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More Plotting
 Creating Plots from the Workspace Window

Plotting Icon
 Editing Plots from the Menu Bar

Copy Figure
10
5
0
-5
-10
30
25
20
20
15
10
10
0
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Summary

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
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Two-Dimensional Plots
Problem Solving Applied
Three-Dimensional Plots
End of Chapter Summary

MATLAB Summary

Characters, Commands and Functions
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Test #3 Review
 MATLAB Environment

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
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MATLAB Windows
Scalar Operations
Array Operations
Saving Your Work
 Predefined MATLAB Functions
 MATLAB Functions
 Manipulating Matrices
 Special Values and Functions
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Test #3 Review
 Plotting


Two-Dimensional Plots
Three-Dimensional Plots
 Applications

Data Analysis
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