plotGAM function

GAM plotting using ggplot2

plotGAM(gamFit, smooth.cov, groupCovs = NULL, orderedAsFactor = T,
  rawOrFitted = F, plotCI = T)

Arguments

• gamFit: fitted gam model as produced by mgcv::gam()
• smooth.cov: (character) name of smooth term to be plotted
• groupCovs: (character) name of group variable to plot by, if NULL (default) then there are no groups in plot
• orderedAsFactor: if TRUE then the model is refitted with ordered variables as factors.
• rawOrFitted: If FALSE (default) then only smooth terms are plotted; if rawOrFitted = "raw" then raw values are plotted against smooth; if rawOrFitted = "fitted" then fitted values are plotted against smooth
• plotCI: if TRUE (default) upper and lower confidence intervals are added at 2 standard errors above and below the mean

Returns

Returns a ggplot object that can be visualized using the print() function

Examples

data <- data.frame(x = rep(1:20, 2), group = rep(1:2, each = 20))
set.seed(1)
data$y <- (data$x^2)*data$group*3 + rnorm(40, sd = 200)
data$group <- ordered(data$group)

gam <- mgcv::gam(y ~ s(x) + group, data=data)

plot1 <- plotGAM(gamFit = gam, smooth.cov = "x", groupCovs = NULL,
                  rawOrFitted = "raw", plotCI=TRUE, orderedAsFactor = FALSE)
gam <- mgcv::gam(y ~ s(x) + group + s(x, by=group), data=data)
plot2 <- plotGAM(gamFit = gam, smooth.cov = "x", groupCovs = "group",
                             rawOrFitted = "raw", orderedAsFactor = FALSE)

See Also

Other Plotting: plotGAMM