11.4 Manual scales

These scales are just a list of valid values that are mapped to the unique discrete values. If you want to customise these scales, you need to create your own new scale with the “manual” version of each: scale_linetype_manual(), scale_shape_manual(), scale_colour_manual(), etc.

The manual scale has one important argument, values, where you specify the values that the scale should produce: see Section 10.3 for an example using manual colour scales. If this vector is named, it will match the values of the output to the values of the input; otherwise it will match in order of the levels of the discrete variable. You will need some knowledge of the valid aesthetic values, which are described in vignette("ggplot2-specs").