Order colors on geom_point for ggplot

Question

I have the following data frame:

dput(df)
 structure(list(convSlope = c(-0.00103951046958614, -0.000107780395196407, 
 1.32997761896617e-05, 2.1532762564503e-05, 6.08499370031235e-05, 
 6.23082414012136e-05, 0.00063868810766659, 0.00137104097264597, 
 0.00138245637682735, 0.00212793023058462, 0, -6.63582853150368e-05, 
 -2.60306132968389e-05, -1.9000297997136e-05, 1.80689291471755e-05, 
 2.41022501949015e-05, 7.68020027582176e-05, 0.000159577537629169, 
 0.000239631350647912, 0.00036196002617637, 0.00210600195850549, 
 0), convLow = c(-0.00864332669999781, -0.0155723308541684, -0.00638165550725293, 
 -0.00647730940467806, -0.00794574690736345, -0.00686551134820207, 
 -0.00727589426769797, -0.00488657681436086, -0.00868933527765364, 
 -0.00412964481046931, -0.0167115021724442, -0.00123221754733313, 
 -0.00373838196002056, -0.00562239375188502, -0.00160896039442434, 
 -0.00237678286364215, -0.0012737092234363, -0.0016402758202216, 
 -0.000878360581920508, -0.000871311121398701, 0.000976025059018948, 
 -0.012527643603177), convHigh = c(0.006565044642425, 0.015400484776708, 
 0.00641124352688413, 0.00651094254026463, 0.00809335314637886, 
 0.00698331294640221, 0.00856088786112379, 0.00763765126215838, 
 0.0114540113784824, 0.00838692108878951, 0.0167115021724442, 
 0.00110057404955679, 0.00368574375564408, 0.00559370035927454, 
 0.00164832488535601, 0.00242147584626002, 0.00142461464553302, 
 0.00196038270799053, 0.00136194408638254, 0.00159190939357683, 
 0.00323693188998354, 0.012527643603177), siteID = c("A", "A", 
 "A", "A", "A", "A", "A", "A", "A", "A", "A", "E", "E", "E", "E", 
 "E", "E", "E", "E", "E", "E", "E"), ID = c("Zyg", "Cho", "Pap", 
 "Bom", "Tor", "Pyr", "Las", "Noc", "Gel", "Geo", "all", "Pap", 
 "Las", "Gel", "Zyg", "Tor", "Bom", "Cho", "Noc", "Pyr", "Geo", 
 "all")), class = "data.frame", row.names = c("13", "12", "11", 
 "10", "9", "8", "6", "3", "2", "1", "14", "15", "141", "131", 
 "91", "81", "71", "51", "41", "31", "17", "16"))

I have created the following plot:

ggplot(df,aes(x= ID, y=convSlope))+
geom_hline(yintercept=0, linetype="solid", color = "grey")+ 
geom_point( col=c("#330066", "#2D0F75", "#281E84","#232D93", "#1E3DA3", "#194CB2", 
 "#145BC1", "#0F6BD1", "#0A7AE0", "#0589EF", "#0099FF",
                "#006600", "#0A7000", "#147A00", "#1E8400", "#288E00", "#339900", 
 "#3DA300", "#47AD00", "#51B700", "#5BC100", "#66CC00"), size= 5)+
geom_pointrange(col=c("#330066", "#2D0F75", "#281E84","#232D93", "#1E3DA3", 
 "#194CB2", "#145BC1", "#0F6BD1", "#0A7AE0", "#0589EF", "#0099FF",
                    "#006600", "#0A7000", "#147A00", "#1E8400", "#288E00", "#339900", 
 "#3DA300", "#47AD00", "#51B700", "#5BC100", "#66CC00"), aes(ymin= convLow, 
 ymax=convHigh))+
geom_hline(yintercept=0.01, linetype="dashed", color = "grey")+ 
geom_hline(yintercept=-0.01, linetype="dashed", color = "grey")+
facet_grid(. ~ siteID)+
theme_bw() + 
xlab("") + 
ylab("Frequency per year")+
theme(strip.text.x = element_text(size=12,
                                face="bold"),
    axis.text.x=element_text(size=rel(1.2), angle=45, hjust = 1),
    axis.title.x=element_text(size=rel(2)),
    axis.title.y=element_text(size=rel(1.75)),
    axis.text.y=element_text(size=rel(1.75)),
    panel.grid.minor=element_blank(),
    panel.grid.major.x=element_blank())

I wish for the point colors to fade from dark to light (dark= leftmost point, light= rightmost point) such that the point for "all" is the darkest point and the point for "Zyg" is the lightest point. Site A should fade from purple to light blue. Similarly, site B should fade from dark green to light green. I listed these colors in order of dark to light in the col argument in geom_point, however the colors sort differently on the graph output.

I need a solution to sort these colors from dark to light for each site.

user_1222578 · Answer

Here's how I would achieve this:

Sort the dataframe by site, and then ID, so it's in the same order it's going to be in the plot
Add the colours to the dataframe so you know they're associated with the right rows
Use aes(colour=colour) and scale_colour_identity() in the actual plot

df <- df[order(df$siteID, df$ID), ]
df$colour <- c("#330066", "#2D0F75", "#281E84","#232D93", "#1E3DA3", "#194CB2", 
                    "#145BC1", "#0F6BD1", "#0A7AE0", "#0589EF", "#0099FF",
                    "#006600", "#0A7000", "#147A00", "#1E8400", "#288E00", "#339900", 
                    "#3DA300", "#47AD00", "#51B700", "#5BC100", "#66CC00")

ggplot(df,aes(x= ID, y=convSlope, colour = colour))+
  geom_hline(yintercept=0, linetype="solid", color = "grey")+ 
  geom_point(size= 5)+
  geom_pointrange(aes(ymin= convLow,  ymax=convHigh))+
  geom_hline(yintercept=0.01, linetype="dashed", color = "grey")+ 
  geom_hline(yintercept=-0.01, linetype="dashed", color = "grey")+
  facet_grid(. ~ siteID)+
  scale_colour_identity() +
  theme_bw() + 
  xlab("") + 
  ylab("Frequency per year")+
  theme(strip.text.x = element_text(size=12,
                                    face="bold"),
        axis.text.x=element_text(size=rel(1.2), angle=45, hjust = 1),
        axis.title.x=element_text(size=rel(2)),
        axis.title.y=element_text(size=rel(1.75)),
        axis.text.y=element_text(size=rel(1.75)),
        panel.grid.minor=element_blank(),
        panel.grid.major.x=element_blank())

Result:

user_9015524 · Answer

A common solution to these kind of problems is to turn the column defining the color into a factor and ordering the levels as desired. In this case a solution that only requires minor changes to your code is possible: Arrange siteID to your required order before turning it into a factor in the arranged order.

df %>% 
  arrange(siteID, ID) %>%
  mutate(ID = fct_inorder(ID)) %>%
ggplot(aes(x= ID, y=convSlope))+
  geom_hline(yintercept=0, linetype="solid", color = "grey")+ 
  geom_point( col=c("#330066", "#2D0F75", "#281E84","#232D93", "#1E3DA3", "#194CB2", 
                    "#145BC1", "#0F6BD1", "#0A7AE0", "#0589EF", "#0099FF",
                    "#006600", "#0A7000", "#147A00", "#1E8400", "#288E00", "#339900", 
                    "#3DA300", "#47AD00", "#51B700", "#5BC100", "#66CC00"), size= 5)+
  geom_pointrange(col=c("#330066", "#2D0F75", "#281E84","#232D93", "#1E3DA3", 
                        "#194CB2", "#145BC1", "#0F6BD1", "#0A7AE0", "#0589EF", "#0099FF",
                        "#006600", "#0A7000", "#147A00", "#1E8400", "#288E00", "#339900", 
                        "#3DA300", "#47AD00", "#51B700", "#5BC100", "#66CC00"), aes(ymin= convLow, 
                                                                                    ymax=convHigh))+
  geom_hline(yintercept=0.01, linetype="dashed", color = "grey")+ 
  geom_hline(yintercept=-0.01, linetype="dashed", color = "grey")+
  facet_grid(. ~ siteID)+
  theme_bw() + 
  xlab("") + 
  ylab("Frequency per year")+
  theme(strip.text.x = element_text(size=12,
                                    face="bold"),
        axis.text.x=element_text(size=rel(1.2), angle=45, hjust = 1),
        axis.title.x=element_text(size=rel(2)),
        axis.title.y=element_text(size=rel(1.75)),
        axis.text.y=element_text(size=rel(1.75)),
        panel.grid.minor=element_blank(),
        panel.grid.major.x=element_blank())

Order colors on geom_point for ggplot

2 Answers