Tool to draw graphs when input points are given

Question

I am writing a dissertation and I have a two collections of data from my research which I would like to compare using graphs. I have the values for abscissa and ordinate and I am looking for some sort of tool into which I can input the values I have and which will plot and trace the graph so I can show the variations in both samples. Just something simple nothing very complicated.

I have been searching the Internet for something like this for hours and I can't seem to find one. What I have found so far are tools which take a function before drawing the graph, but what I need is something which can take the values directly in order to draw the graph connecting them. I don't know whether my search terms are not accurate enough to describe what I need so I hope someone here may be able to help me out.

Please, does anyone know a simple tool which I can use to achieve this? (Windows or - eventually - Linux would be highly appreciated)

Answer 1

R is very good statistical software available free from www.r-project.org It does a lot of complicated stuff, but just connecting dots is easy to show in a demo:

 x1 = c(1,2,3,4,5,6,7)
 y1 = c(5.4, 5.7, 6.2, 6.9, 6.5, 5.8, 4.1)
 # 'plot' sets up axes, labels, etc.
 plot(x1, y1, type="l", col="blue", lty = "dotted",  # 'ell' not 'one'
    ylim=c(0, 8), xlab="Day", ylab="Output", main="Two Lines") 

 x2 = c(1, 3, 4, 7)
 y2 = c(1.3, 4.5, 6.6, 7.8)
 # 'lines' adds broken line to existing plot.
 lines(x2, y2, lwd = 2, col="orange")

 # 'abline' adds axes
 abline(h = 0, col="green2")

Code ? abline, etc. for documentation. colors() for list of colors.

Click on graph, File > Save to export in various formats. If you try this and need more details, please leave a Comment for me.

Answer 2

Most office application suites have some tool to list data and draw plots accordingly. They also allow you to import your data easily.

A free example is Libre Office, with its "Calc" application. The commercial equivalent would be Microsoft Office with Excel.

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Another type of program that can do this are Matlab, Mathematica, MathCAD, and the like, they are general purpose and can do all kinds of numerical and/or symbolical manipulations.

With the free Octave for example, creating and drawing data is easy:

x=0:0.01*pi:2*pi;
plot(x,sin(x));

the above two lines create the following plot. It's also easy to read in existing data and feed that to the plot command.

Answer 3

One option is gnuplot, which handles a lot of graph formats.

More flexible in format (and easier to integrate with LaTeX) is asymptote, but then you have to use a library, and defining the graph is more work.