Multiplot facet line plot in ggplot2 with two Y axes - adding points and changing line colours

Question

I am preparing a multiplot for with two y axes for Inc and Ratio.

I distinguished each plot with different colours to represent three regions. There are three items I am not successful at:

• I do have now, two lines with the same colour in each plot. I would like to change one of them to be dashed (Ratio one).

• I need to add SE bars to Inc line (from Inc column)

• I would like to add geom_points() so there are also points at the nodes where lines are connecting, only for aesthetic reasons.

This is as far as I get:

df <- data.frame(c(2009,2009,2009,2009,2010,2010,2010,2010,2011,2011,2011,2011,
                     2012,2012,2012,2012,2013,2013,2013,2013),
                 c("N","S","W","W","N","S","W","W","N","S","W","W","N","S","W","W",
                   "N","S","W","W"),
                 c("Luo","Aka","Opo","Mya","Luo","Aka","Opo","Mya",
                   "Luo","Aka","Opo","Mya","Luo","Aka","Opo","Mya",
                   "Luo","Aka","Opo","Mya"),
                 runif(20,0,1),runif(20,0,1),
                 runif(20,0,0.1))
colnames(df) <- c("Year","Region","District","Inc","Ratio","Inc_SE")

# Order of drawing in facet
df$District<- factor(df$District,
                            levels = c("Opo",
                                       "Mya",
                                       "Luo",
                                       "Aka"))

p <- ggplot(data=df, aes(x = Year))
p <- p + geom_line(aes(y = Inc)) 
p <- ggplot(df, aes(x = Year, y=df$Inc))
p <- p + geom_line(aes(y = Inc))
p <- ggplot(df, aes(x = Year))
p <- p + geom_line(aes(y = Inc, colour = Region))
p <- p + theme_bw()+
        theme(plot.title = element_text(hjust = 1))+
        theme(legend.position="none")+
        theme(axis.title.x = element_text(face ="bold", colour="black", size=11),
              axis.text.x = element_text(angle=90, vjust=0.5, size=7, family = "serif"),
              axis.title.y = element_text(face = "bold", colour = "black", size=10))

# adding Ratio
p <- p + geom_line(aes(y = Ratio, colour = Region,linetype = "dashed")) # here dashed is not recognised by R
# now adding the secondary axis
p <- p + scale_y_continuous(sec.axis = sec_axis(~.*1, name = "Ratio"))
p <- p + scale_colour_manual(values = c("blue", "red","black"))
p <- p + 
        theme_bw()+
        theme(plot.title = element_text(hjust = 1))+
        theme(legend.position="none")+
        theme(axis.title.x = element_text(face ="bold", colour="black", size=11),
              axis.text.x = element_text(angle=90, vjust=0.5, size=9, family = "serif"),
              axis.title.y = element_text(face = "bold", colour = "black", size=10))
# Breaking down to separate graphs
p_facet = p + facet_wrap(~ df$District, 
                         ncol = 2)
p_facet

Answer 1

You can try a tidyverse. The trick is to transform the data from wide to long (here I used gather). then you can easily add points, lines and Inc_SE as ribbon.

library(tidyverse)
df %>% 
  gather(k,v, -Year, -Region, -District, -Inc_SE) %>% 
  ggplot(aes(Year, v, group = k, color=Region, linetype=k)) + 
    geom_ribbon(data=. %>% filter( k == "Inc"), 
                aes(ymin=v-Inc_SE, ymax=v+Inc_SE), 
                alpha=0.2,color=NA,
                show.legend = F) +
    geom_line() + 
    geom_point(show.legend = F)+
    scale_y_continuous(sec.axis = sec_axis(~.*1, name = "Ratio"))+
    facet_wrap(~ District) +
    labs(y="Inc") + 
    theme_bw() + 
    theme(legend.position = "bottom")