Plotting. Aaron S. Donahue. Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame January 28, 2013 CE20140

Transcription

1 Plotting Aaron S. Donahue Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame January 28, 2013 CE20140 A. S. Donahue (University of Notre Dame) Lecture 4 1 / 15

2 READING QUIZ #1 A. S. Donahue (University of Notre Dame) Lecture 4 2 / 15

3 Notes/Outline for today Plotting in MATLAB (2 Dimensional) Figures Customizing Figures Saving & Printing Figures In Class Plotting A. S. Donahue (University of Notre Dame) Lecture 4 3 / 15

4 2 Dimensional Plotting in MATLAB MATLAB is a powerful tool for the visualization of data. Types of plots Scatter, Line, Bar, Pie, Histogram, Box and Whisker,... Cartesian, Polar,... Adding Details to Plots (required) Axis Labels Figure Title Different style of lines and different plot markers Different line colors Gridlines Multiple plots in the same figure Multiple lines on the same plot Multiple subfigures in the same figure Saving & Printing a Figure A. S. Donahue (University of Notre Dame) Lecture 4 4 / 15

5 Types of Plots Line Plot Functions plot semilogx semilogy loglog plotyy fplot contour, contourf polar Bar Plot Functions bar hist errorbar boxplot Scatter Plot Functions scatter Area Plot Functions pie area fill 3 Dimensional Functions plot3 surf, surfc, surfl imagesc mesh, meshz, meshc, Misc Plot Functions quiver, quiver3 feather compass rose A. S. Donahue (University of Notre Dame) Lecture 4 5 / 15

6 Basic Plotting Commands for Line Plots The most basic plot uses the plot command with two vectors, the syntax is >> plot(x,y) This creates a plot of the vector x vs. the vector y However we often wish to specify specific properties of the line: >> plot(x,y, line specifiers, PropertyName,PropertyValue) ex line specifiers is where the line style, marker style and color for the plot can be given. PropertyName is a particular property of the line that you wish to adjust, such as LineWidth. Note: This is always written as a string with on the outside of the word. PropertyValue is the specific value assigned to the PropertyName, this can sometimes be a value such as with LineWidth or a string such as with MarkerFaceColor This syntax is the same for semilogx, semilogy, and loglog. A. S. Donahue (University of Notre Dame) Lecture 4 6 / 15

7 Line Specifiers You can look up the different line specifiers in MATLAB with the command doc LineSpec or by searching for LineSpec in the help window. Marker Style Specifier Plus Sign + Circle o Asterisk * Point. Cross x Square square or s Diamond diamond or d Upward Triangle ˆ Downward Triangle v Rightward Triangle > Leftward Triangle < 5 pt. Star pentagram or p 6 pt Star hexagram or h Line Style Specifier Solid Line (default) - Dashed Line Dotted Line : Dash Dot Line -. Line/Marker Color Specifier Red r Green g Blue b Cyan c Magenta m Yellow y Black k White w A. S. Donahue (University of Notre Dame) Lecture 4 7 / 15

8 Formatting the Figure Properties Define Axis Limits xlim([xmin xmax]) ylim([ymin ymax] axis([xmin xmax ymin ymax]) Label Axis (required) xlabel( string ) ylabel( string ) Figure Title (required) title( string ) Text placed in Figure text(x,y, string ) Legend (required) legend( Data Set 1, Data Set 2,...) Gridlines on or off grid on or grid off A. S. Donahue (University of Notre Dame) Lecture 4 8 / 15

9 Formatting the Figure Properties Define Axis Limits xlim([xmin xmax]) ylim([ymin ymax] axis([xmin xmax ymin ymax]) Label Axis (required) xlabel( string ) ylabel( string ) Figure Title (required) title( string ) Text placed in Figure text(x,y, string ) Legend (required) legend( Data Set 1, Data Set 2,...) Gridlines on or off grid on or grid off Note: If you search for Text Properties in the help window you will find a list of different properties that can be used to manipulate the axis labels, title and text of a figure. Some examples include ( fontsize,14) Sets the font size to 14 ( color, red ) Sets the font color to red ( rotation,90) Rotates text 90 degrees These are only a few examples of the many things you can do, see the help window for more details. A. S. Donahue (University of Notre Dame) Lecture 4 8 / 15

10 Multiple Plots on the same Figure (Same Axes) Adding additional arguments to the plot command is usually sufficient. >> plot(x1,y1, -o,x2,y2, -- ) Using the hold command allows you to add plots to an axis that is already plotted. >> plot(x1,y1, -o ) >> hold on >> plot(x2,y2, -- ) >> hold off The hold command holds the current axes so new plots can be added. Otherwise the axes would be overwritten by new plot. Note: Be sure to execute the hold off command when you are finished adding plots. A. S. Donahue (University of Notre Dame) Lecture 4 9 / 15

11 Multiple Plots on the same Figure (Subplots) It is also possible to stack multiple plots into one figure with the subplot command. subplot(m,n,p) creates a figure having m rows and n columns, in other words it will have an m n matrix of plots. The designation p is the the location of the current plot being manipulated. >> figure(1) >> subplot(2,1,1) >> plot(x1,y1, -o ) >> subplot(2,1,2) >> plot(x2,y2, -- ) A. S. Donahue (University of Notre Dame) Lecture 4 10 / 15

12 Using the Plot Editor MATLAB s built in Plot Editor can be a useful tool for manipulating plots. It can be accessed in two ways from a figure window. Clicking on the Plot Editor button in the figure window Select either Figure Properties or Axes Properties from the Edit dropdown menu. Some useful features in the Plot Editor are Editing and Adding Text Editing and Adding objects such as arrows, lines, shapes, etc. Editing Marker size, color, style, etc. Editing Line size, color, style, etc. Editing Label, Legends and Title Adjusting Axis Limits One drawback to using the Plot Editor is that it is Manual and thus any adjustments cannot be easily reproduced. A. S. Donahue (University of Notre Dame) Lecture 4 11 / 15

13 Saving and Printing Figures Simply saving a figure in MATLAB from the file dropdown menu saves the figure as a.fig which is a format that only MATLAB can read. In addition printing a figure from the file dropdown menu prints the figure without any ability to adjust size, etc. In general it is not useful to go with the MATLAB default. Saving Use the Save As... option from the File dropdown menu. Choose the.png,.tif or.eps options. (Avoid using the.jpg or.pdf option) Can also use the print command in the command window (This is more advanced, for an example click here:) Printing Import your figure into a Word Processor such as Word or Pages. Resize image so that it is large enough to read. A. S. Donahue (University of Notre Dame) Lecture 4 12 / 15

14 In Class Example Download the.m file entitled In Class 4 Plotting.m from the Resources section of Sakai and follow the instructions. Feel free to work in groups. A. S. Donahue (University of Notre Dame) Lecture 4 13 / 15

15 The following slides give a few examples of the topics discussed in this lecture A. S. Donahue (University of Notre Dame) Lecture 4 14 / 15

16 Basic Plotting Example >> plot(x,y) Given 0 x 2π and y = 0.2 sin(x) >> plot(x,y, r-o, linewidth,4, markersize,10,... markeredgecolor, b, markerfacecolor, g ) go back A. S. Donahue (University of Notre Dame) Lecture 4 15 / 15