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Cartesian coordinates with fixed "aspect ratio"

Source: R/coord-fixed.R
coord_fixed.Rd

A fixed scale coordinate system forces a specified ratio between the physical representation of data units on the axes. The ratio represents the number of units on the y-axis equivalent to one unit on the x-axis. The default, ratio = 1, ensures that one unit on the x-axis is the same length as one unit on the y-axis. Ratios higher than one make units on the y axis longer than units on the x-axis, and vice versa. This is similar to MASS::eqscplot(), but it works for all types of graphics.

Usage

coord_fixed(
  ratio = 1,
  xlim = NULL,
  ylim = NULL,
  expand = TRUE,
  clip = "on",
  reverse = "none"
)

Arguments

ratio

aspect ratio, expressed as y / x

xlim, ylim

Limits for the x and y axes.

expand

If TRUE, the default, adds a small expansion factor to the limits to ensure that data and axes don't overlap. If FALSE, limits are taken exactly from the data or xlim/ylim. Giving a logical vector will separately control the expansion for the four directions (top, left, bottom and right). The expand argument will be recycled to length 4 if necessary. Alternatively, can be a named logical vector to control a single direction, e.g. expand = c(bottom = FALSE).

clip

Should drawing be clipped to the extent of the plot panel? A setting of "on" (the default) means yes, and a setting of "off" means no. In most cases, the default of "on" should not be changed, as setting clip = "off" can cause unexpected results. It allows drawing of data points anywhere on the plot, including in the plot margins. If limits are set via xlim and ylim and some data points fall outside those limits, then those data points may show up in places such as the axes, the legend, the plot title, or the plot margins.

reverse

A string giving which directions to reverse. "none" (default) keeps directions as is. "x" and "y" can be used to reverse their respective directions. "xy" can be used to reverse both directions.

Examples

# ensures that the ranges of axes are equal to the specified ratio by
# adjusting the plot aspect ratio

p <- ggplot(mtcars, aes(mpg, wt)) + geom_point()
p + coord_fixed(ratio = 1)

p + coord_fixed(ratio = 5)

p + coord_fixed(ratio = 1/5)

p + coord_fixed(xlim = c(15, 30))


# Resize the plot to see that the specified aspect ratio is maintained