legend not appearing for ggplot geom_point color aesthetics-CodePudding

I am attempting to generate a legend for ggplot geom_point color aesthetics. I have tried various combinations and browsed through already asked questions but have not come up with a solution.

library (tidyverse)
library (ggplot2)

df <- structure(list(name = c("name1.1", "name1.2", "name1.3", 
                        "name2.1", "name2.2", "name2.3", "name3.1", "name3.2", "name3.3"), 
                     shape = structure(c(1L, 2L, 3L, 1L, 2L, 3L, 1L, 2L, 3L), .Label = c("shape1", "shape2", "shape3"), class = "factor"), 
group_num = structure(c(1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L), .Label = c("group_1", "group_2", "group_3"), class = "factor"), 
x_value = c(0.9, 1, 1.1, 0.9, 1, 1.1, 0.9, 1, 1.1), 
var1 = c(8762, 40679, 49441, 4544, 21064, 25608, 4218, 19615, 23833), 
var2 = c(3.31, 3.02, 3.07, 3.23, 2.88, 2.94, 3.39, 3.17, 3.21), 
var3 = c(28994.1, 122769.8, 151763.9, 14689.2, 60675.8, 75365, 14304.9, 62094, 76398.9), 
var4 = c(230344, 944725, 1175069, 230344, 944725, 1175069, NA, NA, NA), 
var5 = c(26.29, 23.22, 23.77, 50.69, 44.85, 45.89, NA, NA, NA)), row.names = c(NA, -9L), class = c("tbl_df", "tbl", "data.frame"))


df.plot <- ggplot(df, aes(x = x_value, 
                          y = var2))  
  geom_point(aes(
    size = var4,
    shape = shape,
    #color = shape))  
    color = var5),
    alpha = 0.8)  
  scale_shape_manual(values = c("shape1" = 19, "shape2" = 15, "shape3" = 17), name = "Shapes", guide = guide_legend(override.aes = list(size = 3, fill = "black")))  
  scale_size (range = c(2, 10), breaks = c(250000, 500000, 1000000), labels = c("250,000", "500,000", "1,000,000"))  
  #scale_fill_continuous(palette = viridis)  
  #scale_fill_gradient(low="orange2", high="darkblue", na.value ="gray30")  
  scale_color_viridis (breaks = c(10, 15, 21), labels = c("10", "15", "21"), name = "Var5")  
  coord_cartesian(xlim=c(0.7, 1.3), ylim=c(2.8, 3.4))  
  scale_y_continuous(breaks = c(seq (from = 2.8, to = 3.4, by = 0.2)))  
  scale_x_continuous(breaks = c(seq (from = 0.7, to = 1.3, by = 0.1)))  
  geom_point(data = subset(df, is.na(var4)), aes(shape = shape, color = var5),  ####create similar shapes with gray color when var4 and/or var5 are NA
            size = 1.5, fill = "gray30")  
  theme_bw()  
  #guides(color = guide_legend(override.aes = list(size = 3), list(fill = scale_color_viridis ())))  
  theme(panel.grid.major = element_blank(), 
        panel.grid.minor = element_blank(), 
        axis.title.x = element_blank(),
        axis.text.x=element_blank(),
        axis.ticks.x = element_blank())  
  facet_wrap(~ group_num)

Output I get:

If I try without scale_color_viridis (breaks = c(10, 15, 21), labels = c("10", "15", "21"), name = "Var5") I get the following plot.

What I would like to generate is the color legend in the viridis palette.

I have attempted using guide_legend(override.aes) and guides argument outside of aes with no luck

Any help would be appreciated

CodePudding user response：

The problem is that none of your specified breaks fall within the range of the data. There is therefore nothing to colour, and so no scale to show.

range(df$var5, na.rm = T)
#> [1] 23.22 50.69

If you change to say:

scale_colour_viridis_c(breaks = c(10, 15, 21, 30, 40, 50), limits = c(10, 50))

You'll get