visreg (version 3.0.0)

plot.visreg2d: Visualization of regression functions for two variables

Description

Plot method for visualizing how two variables interact to affect the response in regression models, as a ggplot2 raster/contour plot.

Usage

# S3 method for visreg2d
plot(
  x,
  xlab = NULL,
  ylab = NULL,
  zlab = NULL,
  color,
  print_cond = FALSE,
  whitespace = 0.2,
  plot.type = NULL,
  ...
)

Value

A ggplot2 object.

Arguments

x

A visreg2d() object.

xlab, ylab

Axis labels for predictors (default: variable name)

zlab

Label for the color legend (default: outcome variable name)

color

A vector of colors used to establish the color palette for the fill/legend.

print_cond

If print_cond==TRUE, the explanatory variable values conditioned on in a conditional plot are printed to the console (default: FALSE). If print_cond==TRUE and type=="contrast", the conditions will still be printed, but they have no bearing on the plot unless interactions are present.

whitespace

When xvar or yvar is a factor, whitespace determines the amount of space in between the factors. Default is 0.2, meaning that 20 percent of the axis is whitespace.

plot.type

Deprecated, no longer has any effect. See vignette.

...

Not used.

Details

For 3-dimensional surface plots, see persp.visreg2d() (static) or rgl::persp3d() (interactive, requires the rgl package).

References

Breheny P and Burchett W. (2017) Visualization of regression models using visreg. R Journal, 9: 56-71. tools:::Rd_expr_doi("10.32614/RJ-2017-046")

See Also

visreg2d() for creating two-dimensional visreg objects, persp.visreg2d() for static 3D surface plots, and the surface plots vignette for examples and details.

Examples

fit <- lm(
  Ozone ~ Solar.R + Wind + Temp + I(Wind^2) + I(Temp^2) +
    I(Wind * Temp) + I(Wind * Temp^2) + I(Temp * Wind^2) + I(Temp^2 * Wind^2),
  data = airquality
)

visreg2d(fit, x = "Wind", y = "Temp")
visreg2d(fit, x = "Wind", y = "Temp", color = c("purple", "green", "red"))