sqrtAxis function

Determine square root axis tick mark positions

Determine square root axis tick mark positions, including positive and negative range values.

sqrtAxis(
  side = 1,
  x = NULL,
  pretty.n = 10,
  u5.bias = 1,
  big.mark = ",",
  plot = TRUE,
  las = 2,
  cex.axis = 0.6,
  ...
)

Arguments

• side: integer value indicating the axis position, as used by graphics::axis(), 1=bottom, 2=left, 3=top, 4=right. Note that when x is supplied, the numeric range is defined using values in x and not the axis side.

• x: optional numeric vector representing the numeric range to be labeled. When supplied, the numeric range of x is used and not the axis side.

• pretty.n: numeric value indicating the number of desired tick marks, passed to pretty().

• u5.bias: numeric value passed to pretty() to influence the frequency of intermediate tick marks.

• big.mark: character value passed to format() which helps visually distinguish numbers larger than 1000.

• plot: logical indicating whether to plot the axis tick marks and labels.

• las, cex.axis: numeric values passed to graphics::axis()

  when drawing the axis. The custom default las=2 plots labels rotated perpendicular to the axis.

• ...: additional parameters are passed to pretty(), and to graphics::axis() when plot=TRUE.

Returns

invisible numeric vector with axis positions, named by normal space numeric labels. The primary use is to add numeric axis tick marks and labels.

Details

This function calculates positions for tick marks for data that has been transformed with sqrt(), specifically a directional transformation like sqrt(abs(x)) * sign(x).

If x is supplied, it is used to define the numeric range, otherwise the observed range is taken based upon side. If neither x nor side

is supplied, or if the numeric range is empty or zero width, it returns NULL.

The main goal of this function is to provide reasonably placed tick marks using integer values.

Examples

plot(-3:3*10, -3:3*10, xaxt="n")
x <- sqrtAxis(1)
abline(v=x, col="grey", lty="dotted")
abline(h=pretty(par("usr")[3:4]), col="grey", lty="dotted")

# slightly different label placement with u5.bias=0
plot(-3:3*10, -3:3*10, xaxt="n")
x <- sqrtAxis(1, u5.bias=0)
abline(v=x, col="grey", lty="dotted")
abline(h=pretty(par("usr")[3:4]), col="grey", lty="dotted")

See Also

Other jam plot functions: adjustAxisLabelMargins(), coordPresets(), decideMfrow(), drawLabels(), getPlotAspect(), groupedAxis(), imageByColors(), imageDefault(), minorLogTicksAxis(), nullPlot(), plotPolygonDensity(), plotRidges(), plotSmoothScatter(), shadowText(), shadowText_options(), showColors(), usrBox()