A line title for each function and data set appears in the key, accompanied by a sample of the line and/or symbol used to represent it. It can be changed by using the title option.
Syntax:
title <text> | notitle [<ignored text>]
title columnheader | title columnheader(N)
where <text> must either be a quoted string or a string variable. The quotes will not be shown in the key. A special character may be given as a backslash followed by its octal value ("\345"). The tab character "\t" is understood. Note that backslash processing occurs only for strings enclosed in double quotes—use single quotes to prevent such processing. The newline character "\n" is not processed in key entries in either type of string.
There is also an option that will interpret the first entry in a column of input data (i.e. the column header) as a text field, and use it as the key title. See `datastrings`. This can be made the default by speicifying `set key autotitle columnhead`.
The line title and sample can be omitted from the key by using the keyword `notitle`. A null title (`title ”`) is equivalent to `notitle`. If only the sample is wanted, use one or more blanks (`title ' '`). If `notitle` is followed by a string this string is ignored.
If `key autotitles` is set (which is the default) and neither title nor `notitle` are specified the line title is the function name or the file name as it appears on the `plot` command. If it is a file name, any datafile modifiers specified will be included in the default title.
The layout of the key itself (position, title justification, etc.) can be controlled by `set key`. Please see `set key` for details.
Examples:
This plots y=x with the title 'x':
plot x
This plots x squared with title "x^2" and file "data.1" with title "measured data":
plot x**2 title "x^2", 'data.1' t "measured data"
This puts an untitled circular border around a polar graph:
set polar; plot my_function(t), 1 notitle
Plot multiple columns of data, each of which contains its own title in the file
plot for [i=1:4] 'data' using i title columnhead