Example of visreg output plotted with ggplot

visreg-ggplot.R

# library(visreg)
# library(mgcv)
# library(dplyr)

fit <- gam(v1h.v2h.ratio ~ s(v2h.dur, by=v1, k=5) + 
           v1 + v1.is.long + s(speaker, bs='re') + s(word, bs='re'), 
           data=sw.data)

v <- visreg(fit, xvar='v2h.dur', by='v1')

# Some advantages of using ggplot2 here:
# - Consistency with other plots
# - Control over display (as in the plotting of residuals here)
# - Control over what gets shown (here the model includes a set of observations where
#   v1 is \\sw but don't really want that plotted)

ggplot(filter(v$fit, v1 != '\\sw'), aes(v2h.dur, visregFit))+
    geom_line(colour='blue', size=1)+
    geom_ribbon(aes(ymin=visregLwr, ymax=visregUpr), alpha=.3)+
    geom_point(data=filter(v$res, v1 != '\\sw'), aes(v2h.dur, visregRes), size=1, alpha=.3)+
    xlab('Duration of post-tonic vowel')+
    ylab('Effect on V1/V2 ratio')+
    facet_wrap(~v1)