Annotation: log tick marks

Usage

annotation_logticks(base = 10, sides = "bl", scaled = TRUE, short = unit(0.1, "cm"), mid = unit(0.2, "cm"), long = unit(0.3, "cm"), colour = "black", size = 0.5, linetype = 1, alpha = 1, color = NULL, ...)

Arguments

base
the base of the log (default 10)
sides
a string that controls which sides of the plot the log ticks appear on. It can be set to a string containing any of "trbl", for top, right, bottom, and left.
scaled
is the data already log-scaled? This should be TRUE (default) when the data is already transformed with log10() or when using scale_y_log10. It should be FALSE when using coord_trans(y = "log10").
short
a unit object specifying the length of the short tick marks
mid
a unit object specifying the length of the middle tick marks. In base 10, these are the "5" ticks.
long
a unit object specifying the length of the long tick marks. In base 10, these are the "1" (or "10") ticks.
colour
Colour of the tick marks.
size
Thickness of tick marks, in mm.
linetype
Linetype of tick marks (solid, dashed, etc.)
alpha
The transparency of the tick marks.
color
An alias for colour.
...
Other parameters passed on to the layer

Description

This annotation adds log tick marks with diminishing spacing. These tick marks probably make sense only for base 10.

Examples

# Make a log-log plot (without log ticks) a <- ggplot(msleep, aes(bodywt, brainwt)) + geom_point(na.rm = TRUE) + scale_x_log10( breaks = scales::trans_breaks("log10", function(x) 10^x), labels = scales::trans_format("log10", scales::math_format(10^.x)) ) + scale_y_log10( breaks = scales::trans_breaks("log10", function(x) 10^x), labels = scales::trans_format("log10", scales::math_format(10^.x)) ) + theme_bw() a + annotation_logticks() # Default: log ticks on bottom and left

a + annotation_logticks(sides = "lr") # Log ticks for y, on left and right

a + annotation_logticks(sides = "trbl") # All four sides

# Hide the minor grid lines because they don't align with the ticks a + annotation_logticks(sides = "trbl") + theme(panel.grid.minor = element_blank())

# Another way to get the same results as 'a' above: log-transform the data before # plotting it. Also hide the minor grid lines. b <- ggplot(msleep, aes(log10(bodywt), log10(brainwt))) + geom_point(na.rm = TRUE) + scale_x_continuous(name = "body", labels = scales::math_format(10^.x)) + scale_y_continuous(name = "brain", labels = scales::math_format(10^.x)) + theme_bw() + theme(panel.grid.minor = element_blank()) b + annotation_logticks()

# Using a coordinate transform requires scaled = FALSE t <- ggplot(msleep, aes(bodywt, brainwt)) + geom_point() + coord_trans(x = "log10", y = "log10") + theme_bw() t + annotation_logticks(scaled = FALSE)
Warning message: Removed 27 rows containing missing values (geom_point).

# Change the length of the ticks a + annotation_logticks( short = unit(.5,"mm"), mid = unit(3,"mm"), long = unit(4,"mm") )

See also

scale_y_continuous, scale_y_log10 for log scale transformations. coord_trans for log coordinate transformations.