Gnuplot Data Files
A D V E R T I S E M E N T
Gnuplot uses data files for plotting discrete data. These data files are
plain text files which contain numerical data. Comments can be included in file
by placing a pound symbol (#) at the beginning of the line. Each line in the
data file contains exactly one data point, and the numbers on each line must be
separated by blank spaces. These delimit the columns in a data file.
For two-dimensional plots, each data point can have up to 4 columns.
Normally, two columns are used to represent (x, y) pairs. If there are 3
columns, the third column represents the delta value for error bars. Similary,
when there are 4 columns, the last two columns represent the low value and high
value of y, respectively. You can also omit the x column, in which case Gnuplot
will assign x values of 0, 1, 2,... for each successive point. Blank lines
within the data files will cause the plot to be broken between those points.
For three-dimensional plots, each data point can have up to 3 columns.
Normally, three columns are used to represent (x, y, z) triplets. The x and y
columns may be omitted, using the first column for the z column, in which case
Gnuplot will assign x and y values of 0, 1, 2,... for each successive point.
Blank lines within data files in this case separates groups of y-coordinate
points. data files. (With only the z component specified.)
The Gnuplot commands plot and splot use
data files for data plots. See the sections in this tutorial pertaining to data
plots for 2- and 3-dimensional plots.