Ggplot2 outer border of the panel when using a face

Question

I would like to have a border around my grant plot, but not have lines that separate the panels inside the plot. The problem is that panel.border draws a border around each panel in a facet without the ability to just have a border around the entire graph. Alternatively, you can set the inner dividing lines to white, but keep the outer border black.

Here is my code:

mtcars
mtcars$manufacturer=rownames(mtcars)
ggplot(mtcars, aes(x=manufacturer, y=mpg,fill=factor(gear,levels=c("3","4","5"))))+
  geom_bar(stat="identity",position="dodge",colour="black")+
  facet_grid(~cyl,scales = "free_x",space = "free_x",) +
  theme(axis.text.x = element_text(angle = 45,size=12,colour="Black",vjust=1,hjust=1),
    strip.background = element_blank(),
    strip.placement = "inside",
    strip.text = element_text(size=15),
    legend.position=c(0.9,0.8),
    legend.title=element_blank(),
    legend.text=element_text(size=15),
    panel.spacing = unit(0.2, "lines"), 
    panel.background=element_rect(fill="white"),
    panel.border=element_rect(colour="black",size=1),
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank())

Result: Granite site with internal borders

Desired output (edited by paint): Granite graph without internal lines

My actual data graph that I want to delete from the inside is as follows:

Answer 1

, . 2, .

1:

ggplot(df,
       aes(x = Month, y = Abundance, fill = Type)) +
  geom_col(position = "dodge", colour = "black") +
  scale_y_continuous(labels = function(x){paste(x, "-")},    # simulate tick marks for left axis
                     sec.axis = dup_axis(breaks = 0)) +      # add right axis
  scale_fill_grey() +
  facet_grid(~Season, scales = "free_x", space = "free_x") +
  theme_classic() +
  theme(axis.title.y.right = element_blank(),                # hide right axis title
        axis.text.y.right = element_blank(),                 # hide right axis labels
        axis.ticks.y = element_blank(),                      # hide left/right axis ticks
        axis.text.y = element_text(margin = margin(r = 0)),  # move left axis labels closer to axis
        panel.spacing = unit(0, "mm"),                       # remove spacing between facets
        strip.background = element_rect(size = 0.5))         # match default line size of theme_classic

( , .)

2 - 1, . Y :

y.upper.limit <- diff(range(df$Abundance)) * 0.05 + max(df$Abundance)
y.lower.limit <- 0 - diff(range(df$Abundance)) * 0.05

ggplot(df,
       aes(x = Month, y = Abundance, fill = Type)) +
  geom_col(position = "dodge", colour = "black") +
  geom_hline(yintercept = y.upper.limit) +
  scale_y_continuous(labels = function(x){paste(x, "-")},    # 
                     sec.axis = dup_axis(breaks = 0),        # 
                     expand = c(0, 0)) +                     # no expansion from explicitly set range
  scale_fill_grey() +
  facet_grid(~Season, scales = "free_x", space = "free_x") +
  coord_cartesian(ylim = c(y.lower.limit, y.upper.limit)) +  # set explicit range
  theme_classic() +
  theme(axis.title.y.right = element_blank(),                # 
        axis.text.y.right = element_blank(),                 # 
        axis.ticks.y = element_blank(),                      # 
        axis.text.y = element_text(margin = margin(r = 0)),  # 
        panel.spacing = unit(0, "mm"),                       # 
        strip.background = element_blank())                  # hide facet outline

:

set.seed(10)
df <- data.frame(
  Month = rep(c("Jun 14", "Aug 14", "Oct 14", "Dec 14", "Apr 15", "Jun 15"),
             each = 3),
  Type = rep(c("Mangrove", "Mudflat", "Fringe"), 6),
  Season = rep(c("Dry1", rep("Wet1", 3), rep("Dry2", 2)), each = 3),
  Abundance = sample(50:600, 18)
)

df <- df %>%
  mutate(Month = factor(Month, levels = c("Jun 14", "Aug 14", "Oct 14", 
                                          "Dec 14", "Apr 15", "Jun 15")),
         Season = factor(Season, levels = c("Dry1", "Wet1", "Dry2")))

( , facet_grid/facet_wrap ...)