Logistic function to help set alpha opacity

Suggests a alpha opacity to plot with as a function of the number of observation.

Usage

logistic_tform(n, mid_pt = 600, k_attenuation = 5, ceiling = 1, floor = 0.3)

Arguments

n

Number of observations to plot.

mid_pt

Inflection point that the logistic curve. Defaults to 600.

k_attenuation

The steepness of the transition, larger is a sharper transition. Quite sensitive and defaults to 5.

ceiling

The highest number returned. Defaults to 1.

floor

The lowest number returned. Defaults to 0.3.

Value

A scalar numeric, suggested value to set alpha opacity.

See also

Other cheem utility: as_logical_index(), color_scale_of(), contains_nonnumeric(), is_discrete(), is_diverging(), linear_tform(), problem_type(), rnorm_from(), sug_basis(), sug_manip_var()

Examples

library(cheem)

## Suggest an opacity to use in plotting:
(my_alpha <- logistic_tform(nrow(spinifex::penguins_na.rm)))
#> [1] 0.8541665

## Visualize
x <- 1:2000
plot(x, logistic_tform(x), col = "blue")