scale_categorical {ggplot}R Documentation

Scale: general categorical

Description

Create a categorical scale for the specified variable

Usage

scale_categorical(variable="x", name="", expand=c(0,0), transform="as.numeric", ...)

Arguments

variable variable that this scale is for
name name of the scale (used in the legend)
expand expansion factor for scale
transform transformation function
...

Details

A categorical scale is a simple mapping from the levels of the categorical factor to values of the aesthetic attribute. These mappings are created by the aesthetic mapping functions map_colour, and map_linetype. You will want to refer to those to see the possible options that can be used to control the mapping.

You should not call this function yourself. Instead use:

  • pscategorical
  • sccolour
  • sclinetype
  • scshape

    If you use a continuous variable with this scale, it will automatically be converted to a categorical variable using chop_auto. If you want more control over the conversion you will want to use chop yourself. However, be careful to do all the chopping in one place, otherwise you may end up with different scales in different grobs.

    This categorical scale places evenly spaces the levels of the factor along the intergers. If you want to change the order of the levels you will need to change the levels in the original factor.

    Author(s)

    Hadley Wickham <h.wickham@gmail.com>


    [Package ggplot version 0.4.2 Index]