The graphical representation of a mathematical function or a set of data. There are different kinds of plots, such as line plots, bar plots, or scatter plots.
Wikipedia uses the following definition of plot:
A plot is a graphical technique for presenting a data set drawn by hand or produced by a mechanical or electronic plotter. It is a graph depicting the relationship between two or more variables used, for instance, in visualising scientific data.
Plots help greatly in visualizing the structure of your data, or the outcome of an analysis. Good plots yield insight into the data, which is often hard to gain from just looking at the numbers.
r roughly has three separate systems which provide plotting facilities:
- Base plot: these are the plot routines standardly available in R. The syntax works roughly equivalent to MATLAB. The first one creates a
plot, then additional calls to, for example,pointsorlinesadds additional graphical features to the plot. lattice: which provides an implementation of Trellis graphics (S-PLUS) for R.ggplot2: a loose implementation of the grammar of graphics for R.
Different programming platforms support a variety of plot options. Noteworthy are Python's matplotlib - a 2D plotting library which produces publication quality figures in a variety of hardcopy formats and interactive environments across platforms, Matlab's and Mathematica's plot provides the starting point for 2-D line plots, and so forth.
Another widely used library is seaborn; which is a Python data visualization library based on matplotlib. It provides a high-level interface for drawing attractive and informative statistical graphics. For a brief introduction to the ideas behind the library, you can read the introductory notes. Here are a few examples to see what you can do with seaborn.
An additional plotting library is gnuplot. Gnuplot offers easy plotting that can be done through the command line interface. It works for Mac, Windows, Linux, and other operating systems. Gnuplot is very powerful because of the range of options when it comes to types of plots (2d, 3d, histogram, etc.) and the output formats (PNG, EPS, SVG, etc.). More info can be seen here.
