Confidence lines & set order in legend - ggplot

Confidence lines & legend - ggplot.R

# ======================================================================================
# Manually add confidence lines and setting order of line types in legend - ggplot
# The lower and upper values could be computed through bootstrapping.
# ======================================================================================

library(ggplot2)

# create some data
my.data <- data.frame(time     = rep(1:10, 2),
                      means    = 2:21,
                      lowerCI  = 1:20,
                      upperCI  = 3:22,
                      scenario = rep(c("A","Z"), each=10))
my.data

# plot
ggplot(data = my.data) +
    # add the average lines
    geom_line(aes(x=time, y=means, linetype=scenario), lwd=.8) +
    # put "confidence" lines
    geom_line(aes(x=time, y=lowerCI, linetype="CI", group=scenario), lwd=.5, show.legend=FALSE) +
    geom_line(aes(x=time, y=upperCI, linetype="CI", group=scenario), lwd=.5, show.legend=FALSE) +
    # set manually the type of line
    scale_linetype_manual(name = 'Scenario',
                          breaks = c("Z", "A", "CI"),
                          values = c("Z"  = "solid",
                                     "A"  = "twodash",
                                     "CI" = "dotted")) +
    # to set the order in legend as desired one needs to mention that in breaks=() in scale_linetype_manual()
    # also set show.legend=FALSE in geom_line for CI-s so that it doesn’t overlap the legend corresponding to average liens.
    # Note - using a factor for scenario column would not work as expected.
    
    # Final adjustments (optional)
    # set axis labels
    labs(x = "Time", 
         y = "Population growth") +
    # set number of axis ticks
    scale_x_continuous(breaks=pretty(my.data$time, 10)) +
    # eliminate default backgound
    theme_bw() + 
    theme(panel.grid.major = element_blank(), # eliminate major grids
          panel.grid.minor = element_blank(), # eliminate minor grids
          # set font family for all text within the plot ("serif" should work as "Times New Roman")
          # note that this can be overridden with other adjustment functions below
          text = element_text(family="serif"),
          # adjust text in X-axis title
          axis.title.x = element_text(size = 12, face = "bold"),
          # adjust text in Y-axis title
          axis.title.y = element_text(size = 12, face = "bold"),
          # adjust legend title appearance
          legend.title = element_text(size = 10, face = "bold"),
          # adjust legend label appearance
          legend.text = element_text(size = 10),
          # don't draw legend box (check element_rect() for borders and backgrounds)
          legend.background = element_blank(),
          # Put lower-right corner of legend box in lower-right corner of graph
          # Note that the numeric position in legend.position below is relative to the entire area, 
          # including titles and labels, not just the plotting area
          legend.justification = c(1,0),
          legend.position = c(1,0))

# save as pdf
ggsave("Confidence lines & legend - ggplot.pdf", width=10, height=9, units="cm")
# save as png
ggsave("Confidence lines & legend - ggplot.png", width=10, height=9, units="cm", dpi=300)