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scale_fill_manual based on another factor in ggplot2

由 社会主义新天地 提交于 2019-12-05 17:39:31
Henrik

Is this what you want?

library(ggplot2)
library(plyr)
library(gridExtra)

# create data that links colour per 'cat' with 'fishery'
# the 'cat' colours will be used as manually set fill colours. 

# get 'cat' colours

# alt. 1: grab 'cat' colours from plot object
# create a plot with fill = fishery *and* colour = cat
g1 <- ggplot(df, aes(x = year, y = TOTALshark, fill = fishery, colour = cat)) +
  geom_bar(width = 0.5, stat = "identity", position = "dodge") +
  facet_wrap(~ div)

g1

# grab 'cat' colours for each 'fishery' from plot object
# to be used in manual fill
cat_cols <- unique(ggplot_build(g1)[["data"]][[1]]$colour)

# unique 'cat'
cat <- unique(df$cat)

# create data frame with one colour per 'cat'
df2 <- data.frame(cat = cat, cat_cols)
df2


# alt 2: create your own 'cat' colours
# number of unique 'cat'
n <- length(cats)

# select one colour per 'cat', from e.g. brewer_pal or other palette tools 
cat_cols <- brewer_pal(type = "qual")(n)
# cat_cols <- rainbow(n)

# create data frame with one colour per 'cat'
df2 <- data.frame(cat, cat_cols)
df2

# select unique 'fishery' and 'cat' combinations
# in the order they show up in the legend, i.e. ordered ('arranged') by fishery
df3 <- unique(arrange(df[, c("fishery", "cat")], fishery))
df3

# add 'cat' colours to 'fishery'
# use 'join' to keep order
df3 <- join(df3, df2)
df3

# plot with fill by 'fishery' creates a fill scale by fishery,
# but colours are set manually using scale_fill_manual and the 'cat' colours from above
g2 <- ggplot(df, aes(x = year, y = TOTALshark, fill = fishery)) +
  geom_bar(width = 0.5, stat = "identity", position = "dodge") +
  facet_wrap(~ div, nrow = 5) +
  scale_fill_manual(values = as.character(df3$cat_cols))

g2


# create plot with both 'fishery' and 'cat' legend.

# extract 'fisheries' legend
tmp <- ggplot_gtable(ggplot_build(g2))
leg <- which(sapply(tmp$grobs, function(x) x$name) ==  "guide-box")
legend_fish <- tmp$grobs[[leg]]

# create a non-sense plot just to get a 'fill = cat' legend
g3 <- ggplot(df, aes(x = year, y = TOTALshark, fill = cat)) +
  geom_bar(stat = "identity") +
  scale_fill_manual(values = as.character(df3$cat_cols))

# extract 'cat' legend
tmp <- ggplot_gtable(ggplot_build(g3))
leg <- which(sapply(tmp$grobs, function(x) x$name) ==  "guide-box")
legend_cat <- tmp$grobs[[leg]]


# arrange plot and legends

library(gridExtra)

# quick and dirty with grid.arrange
# in the first column, put the plot (g2) without legend (removed using the 'theme' code)
# put the two legends in the second column
grid.arrange(g2 + theme(legend.position = "none"),
             arrangeGrob(legend_fish, legend_cat), ncol = 2) 


# arrange with viewports
# define plotting regions (viewports)
grid.newpage()
vp_plot <- viewport(x = 0.25, y = 0.5,
                    width = 0.5, height = 1)

vp_legend <- viewport(x = 0.75, y = 0.7,
                      width = 0.5, height = 0.5)

vp_sublegend <- viewport(x = 0.7, y = 0.25,
                         width = 0.5, height = 0.3)


print(g2 + theme(legend.position = "none"), vp = vp_plot)
upViewport(0)

pushViewport(vp_legend)
grid.draw(legend_fish)

upViewport(0)
pushViewport(vp_sublegend)
grid.draw(legend_cat)

See also @mnel's answer here for replacing values in the plot object. It might be worth trying here as well. You may also check gtable methods for arranging grobs.

标签
r
ggplot2
legend
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