1. EGR106 Week 6 MATLAB FILES Two Dimensional Plots Multiple Plots
Plot Formatting
Homework

2. MATLAB Files Script files (m files) Data Files (mat files) Text files
Contain MATLAB commands
Data Files (mat files)
binary files
Contain arrays (data)
Use “save” and “load” commands to write and read

3. Two Dimensional Plots Line type Line color Line thickness Markers
plot(x,y,’--’) gives a dashed line
Line color
plot(x,y,’g’) gives a green line
Line thickness
Markers
plot(x,y,’--r*’,’linewidth’,2,’markersize’,12)
Dashed red line with * marker

4. Multiple Plots Plot(x, y1, x, y2) Plots y1 and y2 vs x hold on
Keeps the plot window open for additional lines on the same plot
hold off
Stops writing to the plot
subplot(n,m,k)
Selects plot k in an nxm array of plots.
Used for multiple plots on the same page.

5. Plot Formatting xlabel, ylabel title text legend xlabel(‘time (sec)’)
title(‘Problem 3 Solution’)
text
text(x,y,’your message at coordinates x,y’)
legend
legend(‘first curve’,’second curve’)
used for multiple curves on a single plot

6. Plot Formatting Subscripts and superscripts Greek letters
Rotating text

7. Line Properties and Values
plot(x,y, 'linewidth',5 )
line width
is 5 “points”

8. >> x=0:2:10;
>> y=x.^2;
>> plot(x,y,'--r*','linewidth',2,'markersize',12)
>> text(2,50,'\fontsize{30} \alpha Profit= x^2 ', 'rotation',45)

9. Line Specifiers
plot(x,y, ' r : d ' )
red
dotted line
diamonds

10. Multiple Plots on the Same Axes
Plot allows multiple sets of arrays and line specifiers:
Note colors rotate

11. Two Useful Commands figure ginput(1) alone it opens a new window
figure(n) takes you to window n
ginput(1)
creates crosshairs on the screen
returns (x,y) location of cursor at mouse click
ginput(n) returns n pairs of locations

12. Formatting Plots – Adding Text
Week 1:
xlabel( 'string' )
ylabel( 'string' )
title( 'string' )
text( x, y, 'string' )
New:
gtext( 'string' ) – cursor controlled
legend( 'string1', … 'stringn', loc)

13. Multiple Axes in One Figure - Subplot
plot(x1,y1)
subplot(2,2,2)
etc.
Argument is rows, columns, choice

14. Other Types of 2-D Plots - Polar
x = 1:100;
r = log10(x);
t = x/10;
polar( t, r )
magnitude
angle in radians

15. Other Notes
Line specifiers, properties, axis, grid, … work on many of the plot types
Most of these tools have additional features – use the help function
3-dimensional plots are available (chapter 9) with viewpoint options