Separate out overlapping legend items ggplot()

Question

The Issue

I have a plot that has various lines and symbols. They are all coloured by location ID. This has resulted in the legend items overlapping.

i.e.

There are four symbols: circle, triangle, diamond and square. I need to separate these out from the lines in the legend. To look something like this:

Plot Code

library(ggplot2)
library(ggh4x)         # for facet_wrap2() 

 cols <- c("#ADD8E6","#B4EDD2","#E86A92","#F6AE2D")

 p1 <- ggplot(test, aes(x=DateTime, y=mAODscale, colour=label2)) +
  geom_line() +
  geom_point(data=filter(test, minDate %in% 1), 
             mapping=aes(x=DateTime, y=mAODscale), 
             size=2.5, shape=17) +
  geom_point(data=filter(test, maxDate %in% 1), 
             mapping=aes(x=DateTime, y=mAODscale), 
             size=2.5, shape=16) +
  geom_point(data=filter(test, maxDate2 %in% 1), 
             mapping=aes(x=DateTime, y=mAODscale), 
             size=2.5, shape=18) +
  geom_point(data=filter(test, noMaxDate2 %in% 1), 
             mapping=aes(x=DateTime, y=mAODscale), 
             size=2.5, shape=15) +
  scale_colour_manual(name="", values=cols) +
  facet_wrap2(~fourLoc, ncol=2)
      

Test Data Frame

structure(list(label2 = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 
2L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L), levels = c("B1", "B2", "CH1", 
"CH3"), class = "factor"), DateTime = structure(c(-61781702325, 
-61750166325, -61718630325, -61687094325, -61781702325, -61750166325, 
-61718630325, -61687094325, -61781702325, -61750166325, -61718630325, 
-61687094325, -61781702325, -61750166325, -61718630325, -61687094325
), class = c("POSIXct", "POSIXt"), tzone = ""), fourLoc = structure(c(2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), levels = c("control", 
"test"), class = "factor"), mAODscale = c(0.57, 0.03, 0.24, 0.15, 
0.47, 0.68, 0.55, 0.75, 0.65, 0.62, 0.77, 0.99, 0.98, 0.12, 0.4, 
0.99), minDate = c(0L, 1L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 
0L, 0L, 1L, 0L, 0L), maxDate = c(1L, 0L, 0L, 0L, 0L, 1L, 0L, 
0L, 1L, 0L, 0L, 0L, 1L, 0L, 0L, 0L), maxDate2 = c(0L, 0L, 0L, 
0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 1L), noMaxDate2 = c(0L, 
0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L)), row.names = c(NA, 
-16L), class = "data.frame")

Answer 1

You need to create a variable with the different types (maxDate, maxDate2, ...) that you can map to the shape argument in the aes of geom_point. You can do this when you create a long format of your data (and filter for the relevant entries) with pivot_longer:

test <- structure(list(label2 = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L,2L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L), 
                                          levels = c("B1", "B2", "CH1", "CH3"), class = "factor"), 
                       DateTime = structure(c(-61781702325,-61750166325, -61718630325, -61687094325, -61781702325, -61750166325, 
                                              -61718630325, -61687094325, -61781702325, -61750166325, -61718630325, 
                                              -61687094325, -61781702325, -61750166325, -61718630325, -61687094325), 
                                            class = c("POSIXct", "POSIXt"), tzone = ""), 
                       fourLoc = structure(c(2L,2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), 
                                           levels = c("control", "test"), class = "factor"), 
                       mAODscale = c(0.57, 0.03, 0.24, 0.15,0.47, 0.68, 0.55, 0.75, 0.65, 0.62, 0.77, 0.99, 0.98, 0.12, 0.4,0.99), 
                       minDate = c(0L, 1L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 1L, 0L, 0L), 
                       maxDate = c(1L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 1L, 0L, 0L, 0L), 
                       maxDate2 = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 1L), 
                       noMaxDate2 = c(0L,0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L)), 
                  row.names = c(NA,-16L), class = "data.frame")
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
library(tidyr)
library(ggplot2)
library(dplyr)

test_long <- test %>% 
  pivot_longer(
    cols = minDate:noMaxDate2,
    names_to = "variable",
    values_to = "value"
  ) %>% 
  filter(value == 1)


cols <- c("#ADD8E6","#B4EDD2","#E86A92","#F6AE2D")

ggplot(test, aes(x=DateTime, y=mAODscale, colour=label2)) +
  geom_line() +
  geom_point(data = test_long, aes(x = DateTime, y = mAODscale, shape = variable, group = label2)) +
  scale_colour_manual(name="", values=cols)

^{Created on 2023-08-30 by the reprex package (v1.0.0)}