Plot conditional differences — draw.conditional

Display conditional differences as curves with pointwise or simultaneous intervals and a zero reference line, or as surfaces over two grouped numeric covariates. Each comparison is shown in a separate facet. Surfaces map the difference to fill and, in 3D, height, with a fill range symmetric around zero. Additional conditions supply facets for surfaces, or colour and facets for curves, as in draw.conditional_values().

Usage

# S3 method for class 'conditional_differences'
draw(
  object,
  facet_scales = "fixed",
  discrete_colour = NULL,
  discrete_fill = NULL,
  xlab = NULL,
  ylab = NULL,
  ...,
  surface = c("raster", "tile", "3d"),
  surface_3d = list(),
  continuous_fill = NULL,
  contour = TRUE,
  n_contour = NULL,
  ci_3d = FALSE,
  zlab = NULL
)

Arguments

object: an object returned by conditional_differences().
facet_scales: character; should facets have the same axis scales across facets? See ggplot2::facet_wrap() for details. Options are: "fixed" (default), "free_x", "free_y", and "free".
discrete_colour: a suitable colour scale to be used when plotting discrete variables.
discrete_fill: a suitable fill scale to be used when plotting discrete variables.
xlab: character; label for the x axis of the plot.
ylab: character; label for the prediction axis of a curve, or the second covariate axis of a surface.
...: arguments passed to draw.conditional_values().
surface: character; "raster" (default), "tile", or "3d". Applies to grouped numeric conditions. Three-dimensional surfaces require the optional ggcube package. Irregular flat grids use rectangles bounded by adjacent coordinate midpoints.
surface_3d: named list of view options passed to ggcube::coord_3d(), for example list(yaw = 45, persp = FALSE). The default view uses ggcube::light(backface_scale = 1). A supplied light replaces that lighting specification. The same view applies to all panels; gratia retains its plot theme.
continuous_fill: a suitable fill scale to be used when plotting continuous variables.
contour: logical; draw contour lines on surfaces? Defaults to TRUE.
n_contour: numeric; the number of contour bins. Will result in n_contour - 1 contour lines being drawn. See ggplot2::geom_contour().
ci_3d: logical; add the returned lower and upper interval surfaces when surface = "3d"? Defaults to FALSE.
zlab: character; label for the surface fill legend and 3D height axis. Defaults to the prediction label, or the difference and its scale for conditional differences.

Label layout

Pass label_control = draw_label_control(...) to draw() to wrap discrete axis labels and legend text, stagger discrete tick labels, or adjust legend and colour-bar layout. Settings apply to each panel, including unwrapped plot lists. See draw_label_control() for the available settings.

Examples

load_mgcv()
df <- data_sim("eg4", seed = 2)
m <- gam(y ~ fac + s(x2, by = fac), data = df, method = "REML")
draw(conditional_differences(m, by = "fac", condition = "x2"))