scale_length: Position scales for length or distance data
In EmilHvitfeldt/unitscales: What the Package Does (One Line, Title Case)

Description Usage Arguments Details See Also Examples

This scale allow for easy labeling of data in distance measurements. The scale has two major arguments, 'base' and 'system'. 'system' determine the measurement system, currently "imperial" and "metric" is implemented. For 'base' please refer to details.

scale_x_length(name = waiver(), breaks = waiver(),
  minor_breaks = waiver(), labels = waiver(), limits = NULL,
  expand = waiver(), oob = censor, na.value = NA_real_,
  position = "bottom", sec.axis = waiver(), base = "metre",
  system = "metric", ignore = NULL)

scale_y_length(name = waiver(), breaks = waiver(),
  minor_breaks = waiver(), labels = waiver(), limits = NULL,
  expand = waiver(), oob = censor, na.value = NA_real_,
  position = "left", sec.axis = waiver(), base = "metre",
  system = "metric", ignore = NULL)

`name`	The name of the scale. Used as the axis or legend title. If `waiver()`, the default, the name of the scale is taken from the first mapping used for that aesthetic. If `NULL`, the legend title will be omitted.
`breaks`	One of: `NULL` for no breaks `waiver()` for the default breaks computed by the transformation object A numeric vector of positions A function that takes the limits as input and returns breaks as output
`minor_breaks`	One of: `NULL` for no minor breaks `waiver()` for the default breaks (one minor break between each major break) A numeric vector of positions A function that given the limits returns a vector of minor breaks.
`labels`	One of: `NULL` for no labels `waiver()` for the default labels computed by the transformation object A character vector giving labels (must be same length as `breaks`) A function that takes the breaks as input and returns labels as output
`limits`	A numeric vector of length two providing limits of the scale. Use `NA` to refer to the existing minimum or maximum.
`expand`	Vector of range expansion constants used to add some padding around the data, to ensure that they are placed some distance away from the axes. Use the convenience function `expand_scale()` to generate the values for the `expand` argument. The defaults are to expand the scale by 5% on each side for continuous variables, and by 0.6 units on each side for discrete variables.
`oob`	Function that handles limits outside of the scale limits (out of bounds). The default replaces out of bounds values with `NA`.
`na.value`	Missing values will be replaced with this value.
`position`	The position of the axis. "left" or "right" for vertical scales, "top" or "bottom" for horizontal scales
`sec.axis`	specify a secondary axis
`base`	Character, dertermine what the base unit is, defaults to "metre".
`system`	Character, dertermine what measurement system to use is, defaults to "metric".
`ignore`	Character, which units to ignore.

For "metric", base must be one of

kilometre
metre
centimetre
millimetre
micrometre
nanometre

And for "imperial", base must be one of

mile
yard
foot
inch

Other position scales: scale_x_mass

library(ggplot2)
set.seed(1)
df <- data.frame(
  x = 1:100,
  y = cumsum(rnorm(100)) * 100
)

base <- ggplot(df, aes(x, y)) +
  geom_line()

# Will default to grams
base +
  scale_y_length()

# Different baseline unit can be set with `base` argument
base +
  scale_y_length(base = "millimetre")

# Imperial system also implemented
base +
  scale_y_length(base = "inch", system = "imperial")

# Transformation between systems can be done on the fly. First element
# of system denotes the system you are moving from, and the second element
# denotes the system you are moving to.
base +
  scale_y_length(base = "millimetre", system = c("metric", "imperial"))