Difference between revisions of "Gnuplot/C2/Multiple-plots-in-a-canvas/English"

Title Slide Multiple plots in a canvas

Learning Objectives

• Generate multiple plots in one canvas
• Make a multiplot graph using script commands
• Define placement and size of graphs in canvas

Learning Objectives

• Add a rectangle object in the background
• Generate output on the screen
• Save the output to svg file

Pre-requisites

• Ubuntu Linux 16.04 OS
• Gedit version 3.18
• gnuplot version 5.2.6

System and Software Requirement https:spoken-tutorial.org

• Learner must be familiar with the basics of gnuplot.
• For pre-requisite tutorials, please visit this site.

Code files

• The files used in this tutorial are provided in the Code files link.
• Please download and extract them.

Enter the command cd Desktop.

I will demonstrate the multiplot command, with four graphs in one canvas.

The ampersand makes the process run in the background.

It detaches the process from the terminal.

Windows users may use notepad or wordpad.

We will write the required commands in a text file.

This is a comment line.

Start a new line and leave a blank line for clarity.

#x-sin(x) plot

In the next line, enter a comment to identify that, the plot is for sin x.

set origin 0,0 set size 0.5, 0.5

They define the size and placement for the sin x plot.

This is the left hand bottom corner of the page.

This size is relative to the total page size and makes it a quarter of the page.

set xrange[-10:10] yrange[-2:2] set title '”x-sin(x) plot”

These are the graph formatting details for the sin x plot.

# cos (x) - x plot

First, write a comment line, to indicate it is the part for cos (x), in the script.

Type hash cos x-x plot.

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

Pause the video as and when necessary.

The position is set to the right side of the sin x plot.

This file is provided to you in the Code files link of this tutorial.

#straight line plot

Write a comment, starting with a hash.

Type, straight line plot and press Enter.

set origin 0.5,0.5

set size 0.5, 0.5

This position places the graph in the top right corner.

set title "straight line" set xrange[*:*] set yrange[*:*] plot 'data.txt' using 1:3 with linespoint notitle and press Enter.

Specify the title, autoscale axis range and issue the plot command.

Hover mouse next to notitle.

Here I also specify, no legend title is required in the plot.

press Enter.

set origin 0.0,0.5 and press Enter.

set size 0.5, 0.5 set title "Exponential decay" set autoscale plot 'data.txt' using 1:2 with linespoint notitle and press Enter.

Read in the columns for x and y data from the data file in the plot command.

Here, it is column 1 and column 2 for x and y data.

Type unset multiplot and press Enter.

Finally, unset the multiplot mode with the command, unset space multiplot.

Click on save.

Click on save to save the script.

If so, type unset space multiplot.

If we do not unset the format, the set format will not reset to default setting.

Debug the script to make it error free and run the script to generate the plot.

Close the graphics window.

If you had closed it, please open the script file to edit it further.

Start a new line before plot command.

Let's change the background color of the sin x plot.

Start a new line before the plot command.

set object 1 rectangle from graph 0,0 to graph 1,1 behind fillcolor rgb 'cyan' fillstyle solid noborder and press Enter.

Enter the command as seen on the screen.

Type, unset object 1 and press Enter.

Unset the cyan background object, as shown here.

set format y "10^{%L}" set xtics rotate set ytics 40000 and press Enter.

The y axis numbers are large.

So I will change the notation.

I will also rotate the x axis tics in the plot.

I also specify the y tics spacing.

set format y "10^{%L}" set xtics rotate set ytics 40000 and press Enter.

Notice that, they are added before the plot command.

Scroll up to the top of the script file.

set terminal svg size 800,800 enhanced font 'Verdana,12'

set output 'multiplot.svg' and press Enter.

These are done before the multiplot command is executed.

This is done after before we unset the multiplot mode.

If you had closed gnuplot, please open gnuplot again.

Now, the graphics window does not open, since the output is a svg file.

Since the path is Desktop the output file is generated in the Desktop directory.

Practise and familiarize with the commands and styles.

Summary

• Learned the multiplot command
• Defined placement and size of plot in canvas
• Generated four plots in a canvas
• Added a rectangle object
• Generated output on the screen and
• Saved the output to a svg file

Assignment 1

• Plot 4 parabolas opening in 4 different quadrants in a 2 x 2 multiplot.

• Give a different background color for each plot.

Assignment 2

• Generate one plot covering the canvas with x-y1 data points.
• Draw an inset graph, with x-y2 data points.

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Acknowledgement

Thank you for joining.