Gnuplot/C2/Plotting-datasets-from-file/English
Visual Cue | Narration |
Slide Number 1
Title Slide Plotting datasets from file |
Welcome to the tutorial on Plotting datasets from file |
Slide Number 2
Learning Objectives |
In this tutorial we will learn to,
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Slide Number 3
System and Software Requirement |
To record this tutorial, I am using
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Slide Number 4
Pre-requisites |
To follow this tutorial, learner's must be familiar with,
and
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Go to Desktop | Go to Desktop
We will plot a graph from data in a text file data dot txt The file is provided with this tutorial. |
Show data.txt icon in Desktop directory. | It is saved in the Desktop folder for me. |
Double click on the icon | Double click on the file icon to open and view the file.
File opens in gedit text editor for me |
Hover over mouse over hash. | Data has three columns.
The first row consists of headers and starts with a hash |
First column contain x data.
2nd and 3rd columns are two sets of y data. | |
Click on x sign | Close the file by File > quit or click on the 'x' sign |
Press ctrl+alt+t | Press control alt t, keys together on keyboard, to open a terminal |
A terminal opens. | |
cd Desktop | Change directory to Desktop directory with command as seen on the screen. |
gnuplot, clear screen, | Type gnuplot in command prompt and press enter, to open gnuplot
I will bring terminal plot to top of the screen for clarity |
Hight on screen,
>plot "data.txt" using 1:2 title 'Y1' |
First let's make a plot from x and y1 data columns.
Enter command as seen on the screen |
replot | Here we also added legend in the same command line
A graphic window opens Next, let's make the symbol size larger |
Type set pointsize 1.5
Press enter |
To set symbol point size, type set pointsize 1.5
Press enter |
replot | Replot to see the updated graph
You may pause the video and explore symbol size and choose a size of your choice |
Now, Say I want to compare both y1 and y2 data on x-axis | |
plot "data.txt" using 1:2 title 'Y1' , "data.txt" using 1:3 title 'Y2' | For this purpose, use the plot command as above, in series, separated by a comma
The command is shown on the screen. |
Let's set yaxis to logarithmic scale from linear next | |
>set logscale y
replot |
Use command set space logscale space y to set logscale.
Replot to see the result. |
Show in Graphic window | The exponential curve change to linear line due to the logarithmic scale |
>unset logscale y | To go back to linear scale for y axis, use command, unset space logscale space y |
>replot | Please replot to see the resulting change.
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plot "data.txt" using 1:3 with linespoints | Say, I desire to draw a line between data points for x and y2 data set.
I will use the command as seen on the screen. |
Add with lines points in the plot command itself. | |
Next, let's change few graph properties.
Say, I want a larger size filled circle data points and color them blue. | |
Highlight on screen
>plot "data.txt" using 1:3 title 'Y2' with linespoint lc 'blue' lt 1 lw 2 pt 7 ps 1.5 |
Enter the command, as seen on the screen.
This changes color, point style and style line. |
Hover mouse next to lc | Here, lc sets line color to blue.
We can also use hexadecimal code for a chosen color. |
Hover mouse over lw | And lLw 2 sets line width to two |
Hover mouse next to pt | Pt sets point type or symbol style to 7, which is a filled circle. |
Hover mouse next ps | Ps sets point size or symbol size to 1.5 |
Hover mouse on y-axis range | We may wish to change the format for axis labels on many occasions.
Here, the y-axis numbers are large. |
We may want to use scientific notation.
I will use set format command for this purpose. | |
>Set format y | Type set space format, followed by axis name.
Here it is y. |
'%0.2e' and replot | Follow it by percent sign 2 e within single quotes as in the video. |
You may also use the following syntax for changing format and range. | |
>set yrange [1:1.5e5] and replot | Use set space yrange space 1 colon 1 point 5e5 in square braces
This also changes format of y axis |
clear screen
set border linewidth 2 lc 'red' |
I will bring terminal prompt to top of the screen, for clarity.
We can also change color of the border and the line width. The commands are shown on the screen. |
>set timestamp | We may also want to have a time stamp with the graph.
Type set space timestamp to add time stamp |
Notice time stamp for the plot is displayed on bottom of the plot | |
Slide Number 5
Summary |
To summarize, in this tutorial, we
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Slide Number 6
Summary |
* Learned to change symbol style and size
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Slide Number 7
Summary |
For assignment activity, please do the following,
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Slide Number 8
Spoken Tutorial Project |
This video summarizes the Spoken Tutorial Project
Please download and watch it. |
Slide Number 9
Spoken Tutorial workshops |
We conduct workshops and give certificates.
Please write to us. |
Slide Number 10
Forum for specific questions: |
Post your timed queries in the forum. |
Slide Number 11
Acknowledgement |
Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India. |
Thank you for joining. |