Gnuplot/C2/Multiple-plots-in-a-canvas/English
| Visual Cue | Narration |
| Slide Number 1
Title Slide Multiple plots in a canvas |
Welcome to the tutorial on Multiple plots in a canvas |
| Slide Number 2
Learning Objectives |
In this tutorial, we will learn to,
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| Slide Number 3
Pre-requisites |
To record this tutorial, I am using,
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| Slide Number 4
System and Software Requirement |
To follow this tutorial, learners must be familiar with,
Basic computer and internet skills Concept of graphing and College level Mathematics skills |
| Multiplot command allow us to plot multiple graphs in a single plotting canvas.
I will demonstrate with four separate graphs in one canvas | |
| Press ctrl alt t
cd Desktop |
Press control alt t keys together to open a terminal.
Change to Desktop directory. |
| Gedit
press enter |
Type gedit and press enter, to open gedit.
We will write the commands in a text file and run the script file to plot graph. |
| I will use gedit text editor, windows users may use notepad software.
We can edit the script file to make any required changes in the graph. | |
| # my first multiplot and press enter | I will type hash my first multiplot and press enter
This is a comment line |
| Next, type the commands as seen in the video.
I will explain them to you. | |
| set multiplot, press enter | First, set the environment to multiplot as set space multiplot
Start a new line |
| We will plot, sin x, cos x, a straight line and an exponential decay curve.
I will start with the script for sin x
| |
| Highlight and type
#x-sin(x) plot |
Enter the commands, as seen in the video to specify placement and size |
| Highlight and type
set origin 0,0 set size 0.5, 0.5 |
The plot is set in position 0 , 0 in origin
Here I am specifying plot size to be a square of point 5 by point 5 |
| Highlight and type,
set xrange[-10:10] set yrange[-2:2] set title '”x-sin(x) plot” plot sin(x) |
Next, we will set x and y range, and title
Then, issue the plot command. |
| Type,
# x-cos (x) plot |
Now, I will enter details for the second plot, x, cos x.
First, write a comment to indicate it is the part of the script for cos x. Type hash x cos x plot. Press enter. |
| set origin 0.5,0.0
set size 0.5, 0.5 set xrange[-10:10] set yrange[-2:2] set title "x-cos(x) graph" plot cos(x) notitle |
Enter commands as seen in the video.
When necessary, pause the video. Here, I specify the position and size of the second plot. Set position of the plot to the right of x sin x plot. |
| For third and fourth plots, I will use the data from a text file.
It is named ‘’’data dot txt’’’ and saved in the desktop directory for me. The file is also provided to you with the tutorial. | |
| Type
#straight line plot |
Now, I will enter details for the third plot.
Make a comment, starting with a hash. Type, straight line plot and press enter Again specify the size and position. Position places the graph on top right corner. |
| set origin 0.5,0.5
set size 0.5, 0.5 set title "straight line" set xrange[*:*] set yrange[*:*] plot 'data.txt' using 1:3 with linespoint notitle |
Enter commands as seen in video.
Please pause the video when required. Enter the formatting properties for the plot. |
| Hover mouse over origin, xrange and yrange | The stars specifies auto scale for axis range.
Issue the plot command in the end. Here, I want column one as x data and column three as y data. In the plot command, I also specify, no legend title is required. |
| Next, let's write script to generate the exponential decay plot. | |
| Type, #Exponential decay | I will type hash exponential decay for the comment. |
| set origin 0.0,0.5 | Set position to top left, above the sin x plot
Set size and title for the graph. |
| set size 0.5, 0.5
set title "Exponential decay" set autoscale plot 'data.txt' using 1:2 with linespoint notitle |
I will also autoscale the data for axis range.
I will read the x and y data from the data file in the plot command Here, column one and column two are used for x y data. |
| >unset multiplot | Finally, unset the multiplot mode with command, unset space multiplot |
| Press ctrl-S | Press ctrl-S to open the file save dialogue box. |
| Type filename, multiplot.dem
click on save |
I will give file name multiplot dot dem and choose Desktop directory for path.
Click on save to save the script |
| Minimize gedit
open terminal |
Click to minimize gedit.
Let's open another terminal. |
| Ctrl alt t | Press control atl t keys together to open a terminal
|
| cd Desktop” | Change directory to desktop |
| Type, gnuplot
Press enter |
Open gnuplot from this terminal |
| Press control shift k. | I will clear the screen and bring prompt to top of the screen for clarity in video.
Let's run the script to generate the multiplot. |
| load 'multiplot.dem'
Press enter |
Type load space in single quotes, multiplot dot dem
Press enter |
| A graphics window with four graphs in the canvas opens.
I notice a few formatting modifications could improve the view. | |
| Close the graphics window. | Hence, make the modifications in the script next.
Close the graphics window. |
| Go back to gedit script | Go back to gedit to edit the script.
If you had closed it, please open the script file to edit it further. |
| Let's change the background color of the sin x plot. | |
| set object 1 rectangle from graph 0,0 to graph 1,1 behind fillcolor rgb 'cyan' fillstyle solid noborder | Scroll to the sin x script and start a new line before the plot command.
To change background color, we will insert an object, in the graph. Enter the command as seen in the video. |
| Hover mouse next to cyan and noborder | Here, we set a rectangle object, with cyan color for background, without border. |
| unset object | After the plot command unset the object
Type, unset space object |
| set format y "10^{%L}"
set xtics rotate set ytics 40000 |
Next, add modifications on the script on axis formats, for straight line plot.
Enter the commands as seen in the video. |
| Hover mouse over the change. | The y axis numbers are large.
So I will change the notation. I will also rotate the x axis label y tics spacing. |
| unset format y | Unset y axis format after the plot command is executed. |
| Next, go to the exponential decay part. | |
| set format y "10^{%L}"
set xtics rotate set ytics 40000 |
Add the formatting commands, before the plot command as seen on the screen |
| This specifies y axis label format and rotates x axis label
Set y tics spacing to forty thousand. | |
| Type, unset format y | Start a new line after plot command.
Enter command unset space format space y to unset y axis format. |
| Now let’s add command to print the graph to an image file. | Scroll up to the top of the script. |
| set terminal svg size 800,800 enhanced font 'Verdana,12'
set output 'multiplot.svg' |
Set terminal to svg as seen in the video.
Svg is scalable vector graphics. |
| Direct the output to a svg file
This is done before the multiplot command is executed | |
| unset output
ctrl s |
Scroll to the bottom of script file and unset the output
Type unset space output Press ctrl s to save the file. |
| Go to terminal
>load 'multiplot.dem' Press enter |
Minimize gedit.
Go back to terminal where gnuplot was open. Run the updated multiplot dot dem script. |
| If you had closed gnuplot, please open gnuplot again
This time, the output is directed to a file. The graphics window does not open. The output file is generated in the Desktop directory. | |
| In case of errors in the script, gnuplot may remain in multiplot mode.
If so, type unset space multiplot This returns to gnuplot prompt | |
| Go to Desktop | Go to Desktop |
| Open multiplot.svg | Double click on the multiplot dot svg file icon to view it. |
| You may add desired formatting to the script file.
Notice the cyan background only in the the x sin x plot | |
| Similar scripts are available in gnuplot demo website.
I encourage you to practice and familiarize with commands and styles. | |
| Slide Number 5
Summary |
Now, to summarize, in this tutorial, we
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| Slide Number 6
Assignment |
For assignment activity, please do the following.
Plot 4 parabolas opening in 4 different quadrants, in a 2 by 2 multiplot |
| Slide Number 7
Spoken Tutorial Project |
This video summarises the Spoken Tutorial Project
Please download and watch it. |
| Slide Number 8
Spoken Tutorial workshops |
We conduct workshops and give certificates.
Please write to us. |
| Slide Number 9
Forum for specific questions: |
Post your timed queries in the forum. |
| Slide Number 10
Acknowledgement |
Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India. |
| This is Rani from IIT Bombay.
Thank you for joining. |
