8.27.19 key

set key [ <position> ... ] [<xoffset>, <yoffset>]

The setting key determines whether a legend is placed on a plot, and if so, where it should be located on the plot. Issuing the command:

set key

simply causes a legend to be added to the plot in its default position, usually the plot’s upper-right corner. The converse action is achieved by:

set nokey

or:

unset key

both of which cause a plot to have no legend. A position for the key may also be specified after the set key command, for example:

set key bottom left

Recognised positions are top, bottom, left, right, below, above, outside, xcentre and ycentre. In addition, if none of these quite achieved the desired result, a positional offset may be specified after one of the position keywords above. The first value is assumed to be an $x$-offset, and the second a $y$-offset, in centimetres. For example:

set key bottom left 0.0, -0.5

would display a key below the bottom left corner of the graph.