sfsmisc (version 1.1-19)

axTexpr: Axis Ticks Expressions in Nice 10 ** k Form

Description

Produce nice \(a \times 10^k\) expressions for axis labeling instead of the scientific notation "a E<k>".

Usage

axTexpr(side, at = axTicks(side, axp = axp, usr = usr, log = log),
        axp = NULL, usr = NULL, log = NULL,
        drop.1 = FALSE)

Value

an expression of the same length as x, with elements of the form a %*% 10 ^ k.

Arguments

side

integer in 1:4 specifying the axis side, as for axis.

at

numeric vector; with identical default as in axTicks().

axp, usr, log

as for axTicks().

drop.1

logical indicating if \(1 \times\) should be dropped from the resulting expressions.

Author

Martin Maechler

Details

This is just a utility with the same arguments as axTicks, a wrapper pretty10exp(at, *).

See Also

pretty10exp; eaxis, axis, axTicks.

Examples

x <- 1e7*(-10:50)
y <- dnorm(x, m=10e7, s=20e7)
plot(x,y)## not really nice,  the following is better:

## For horizontal y-axis labels, need more space:
op <- par(mar= .1+ c(5,5,4,1))
plot(x,y, axes= FALSE, frame=TRUE)
aX <- axTicks(1); axis(1, at=aX, label= axTexpr(1, aX))
## horizontal labels on y-axis:
aY <- axTicks(2); axis(2, at=aY, label= axTexpr(2, aY), las=2)
par(op)

### -- only 'x' and using log-scale there:
plot(x,y, xaxt= "n", log = "x")
aX <- axTicks(1); axis(1, at=aX, label= axTexpr(1, aX))

## Now an "engineer's version" ( more ticks; only label "10 ^ k" ) :

axp <- par("xaxp") #-> powers of 10 *inside* 'usr'
axp[3] <- 1 # such that only 10^. are labeled
aX <- axTicks(1, axp = axp)
xu <- 10 ^ par("usr")[1:2]
e10 <- c(-1,1) + round(log10(axp[1:2])) ## exponents of 10 *outside* 'usr'
v <- c(outer(1:9, e10[1]:e10[2], function(x,E) x * 10 ^ E))
v <- v[xu[1] <= v & v <= xu[2]]

plot(x,y, xaxt= "n", log = "x", main = "engineer's version of x - axis")
axis(1, at = aX, label = axTexpr(1, aX, drop.1=TRUE)) # 'default'
axis(1, at = v,  label = FALSE, tcl = 2/3 * par("tcl"))