CODEWITHSUNDEEP
rggplot2facetfacet-wrap
Deni Galinac Ribičić
Deni Galinac Ribičić

Reputation: 77

ggplot2: Create facet in facet

I don't know whether I have expressed myself correctly in the title, but I hope it is easy to understand when you see the following figures. For the start, this is my data:

hydrocarbons    average SD  type    group
N   6,21    4,632774217 PAHs    Naphtalenes
N1  4,71    2,43670665  PAHs    Naphtalenes
N2  7,6 3,266286228 PAHs    Naphtalenes
N3  16,18   11,00643289 PAHs    Naphtalenes
N4  18,8    4,59631824  PAHs    Naphtalenes
F   16,87   7,022165062 PAHs    Fluorenes
F1  16,64   5,721267073 PAHs    Fluorenes
F2  18,67   8,467132345 PAHs    Fluorenes
F3  22,79   0,988021105 PAHs    Fluorenes
P   7,97    0,211647391 PAHs    Phenanthrenes
P1  26,66   16,64819987 PAHs    Phenanthrenes
P2  21,72   4,416811664 PAHs    Phenanthrenes
P3  18,99   4,635405486 PAHs    Phenanthrenes
P4  66,28   7,706085861 PAHs    Phenanthrenes
D   8,33    0,89862145  PAHs    Dibenzothiophenes
D1  8,63        PAHs    Dibenzothiophenes
D2  9,57        PAHs    Dibenzothiophenes
D3  20,69   3,453922632 PAHs    Dibenzothiophenes
D4  32,5    8,191613185 PAHs    Dibenzothiophenes
FL  10,37       PAHs    Fluoranthenes
PY  10,53       PAHs    Fluoranthenes
FL1 24,42   8,886055918 PAHs    Fluoranthenes
FL2 42,52   9,466539232 PAHs    Fluoranthenes
FL3 51,99   15,77786373 PAHs    Fluoranthenes
C   74,28   9,560499532 PAHs    Chrysenes
C1  46,56   15,86163409 PAHs    Chrysenes
C2  82,85   4,854714782 PAHs    Chrysenes
C3  114,42  41,70884318 PAHs    Chrysenes
nC-10   2,24        alkanes 
nC-11   2,24        alkanes 
nC-12   4,85    1,414267191 alkanes 
nC-13   5,54    0,089306765 alkanes 
nC-14   6,81    0,241222891 alkanes 
nC-15   5,56        alkanes 
nC-16   5,95        alkanes 
nC-17   5,82        alkanes 
nC-18   5,7     alkanes 
nC-19   6,41        alkanes 
nC-20   7,36        alkanes 
nC-21   6,24        alkanes 
nC-22   6,07        alkanes 
nC-23   6,35        alkanes 
nC-24   7,32        alkanes 
nC-25   6,6 2,215395794 alkanes 
nC-26   5,97    1,839829721 alkanes 
nC-27   6,51    1,972060107 alkanes 
nC-28   7,57    1,797509743 alkanes 
nC-29   8,37    3,004883333 alkanes 
nC-30   9,05    3,503601406 alkanes 
nC-31   10,27   4,242811665 alkanes 
nC-32   11,5    5,087821955 alkanes 
nC-33   14,31   8,085948386 alkanes 
nC-34   16,96   10,10105484 alkanes 
nC-35   20,52   14,1878649  alkanes 
nC-36   21,88   13,40071226 alkanes 
n-C5 (Pentane)  10,63   1,715015757 VOCs    
n-C6 (Hexane)   1,74    0,859880844 VOCs    
n-C7 (Heptane)  9,62    4,316473516 VOCs    
n-C9 (Nonane)   2,34    0,044641    VOCs    
Benzene 23,51   0,631882255 VOCs    
Toluene 18,48   2,369137637 VOCs    
Ethylbenzene    7,55    7,171631537 VOCs    
m-Xylene    12,53   7,250491275 VOCs    
p-Xylene    15,21   1,800247445 VOCs    
o-Xylene    21,96   2,184177383 VOCs    
Propylbenzene   12,8    15,31136895 VOCs    
n-Butylbenzene  9,33    5,486543125 VOCs    
n-Pentylbenzene 6,77    0,420247353 VOCs

I want to plot half-lifes ("average") of my hydrocarbons and facet it according the "type". However, only for type "PAHs" I would like to have additional facet according the "group". The best I was able to code and plot is the following figure and it's not quite what I want : hydrocarbon_halflifes

This is the code I'm using:

all <- read.delim2("E#6-results_chemistry.txt", header=TRUE)
library(ggplot2)
all$hydrocarbons <- factor(all$hydrocarbons, levels = all$hydrocarbons) #keeps the order of x-axis same as in table
levels(all$type)[levels(all$type)=="alkanes"] <- "n-alkanes" #if needed to change specific labels in a column
ggplot(all, aes(x=hydrocarbons, y=average)) +
  geom_bar(position = position_dodge(), stat="identity", fill="gray32") + 
  geom_errorbar(aes(ymin=average-SD, ymax=average+SD), color="gray8") + 
  facet_wrap(~type, scales="free", ncol=1) +
  ylab("Half-life [d]") + xlab("Hydrocarbons") +
  theme(axis.text.x=element_text(size=12, color="black", angle=45, hjust=1),
axis.title.x = element_text(size=14, face="bold", vjust=-0.7), 
axis.title.y = element_text(size=14, face="bold", vjust=2),
axis.text.y = element_text(size=12, colour="black"))

Now, the question is, Is it possible to make a graphic where I would be able to make an additional facet strip, within existing one, only for "PAHs" type according to the "group"? The graphics would look something like this: facet_in_facet

It would also work for me, if possible, to make a second x axis for "PAHs" which would arrange it according the "group".

Thanks, Deni

Upvotes: 4

Views: 301

Answers (1)

Sandy Muspratt
Sandy Muspratt

Reputation: 32859

I think you will need to delve into the ggplot structure. This approach takes your original plot, but drops the middle panel (but keeps the space). I construct the middle panel as a separate plot, including the facets for the levels of 'PAHs'. I extract the relevant material (plot panel, strips, x-axis, and y-axis) from this plot to insert it into the empty spaces in the original plot. Then, I construct a new strip to contain the variable name 'PAHs'. The method ensures that the heights of the three panels are the same, unit(1, "null"). (See below after the plot for the all data frame that I used.)

Minor edit: Updating to ggplot2 2.2.1

library(ggplot2)
library(gtable)
library(grid)
all$hydrocarbons <- factor(all$hydrocarbons, levels = all$hydrocarbons) #keeps the order of x-axis same as in table
   levels(all$type)[levels(all$type)=="alkanes"] <- "n-alkanes" #if needed to change specific labels in a column

# Original plot
pAll <- ggplot(all, aes(x = hydrocarbons, y = average)) +
  geom_bar(position = position_dodge(), stat="identity", fill = "gray32") + 
  geom_errorbar(aes(ymin = average-SD, ymax = average+SD), color = "gray8") + 
  facet_wrap( ~ type, scales = "free", ncol = 1) +
  ylab("Half-life [d]") + xlab("Hydrocarbons") +
  theme(axis.text.x = element_text(size = 12, color = "black", angle = 45, hjust = 1),
     axis.title.x = element_text(size = 14, face = "bold", vjust = -0.7), 
     axis.title.y = element_text(size = 14, face = "bold", vjust = 2),
     axis.text.y = element_text(size = 12, colour = "black"))

# Middle plot, but with facets for 'PAHs'
pMid <- ggplot(subset(all, type == "PAHs"), aes(x = hydrocarbons, y = average)) +
  geom_bar(position = position_dodge(), stat = "identity", fill = "gray32") + 
  geom_errorbar(aes(ymin = average - SD, ymax = average + SD), color = "gray8") + 
  facet_grid(. ~ group, scales = "free", space = "free") +
  ylab("Half-life [d]") + 
  theme(axis.text.x = element_text(size = 12, color = "black", angle = 45, hjust = 1),
     axis.title.x = element_text(size = 14, face = "bold", vjust = -0.7), 
     axis.title.y = element_text(size = 14, face = "bold", vjust = 2),
     axis.text.y = element_text(size = 12, colour = "black"))

# Get the ggplot grobs
gAll <- ggplotGrob(pAll)
gMid <- ggplotGrob(pMid)

# In gMid, get the positions of the panels in the layout: t = top, l = left, ...
pos1 <- c(subset(gMid$layout, grepl("panel", gMid$layout$name), select = t:r))

# Extract 'panels' (along with x-axis and strips)
panels <- gMid[(unique(pos1$t) - 1) : (unique(pos1$t) + 1), min(pos1$l) : max(pos1$l)]
# Extract 'axisL' - y-axis
axisL <- gMid[unique(pos1$t), min(pos1$l) - 1]

# In gAll, get the positions of the panel of the middle plot in the layout
pos2 <- c(subset(gAll$layout, grepl("panel", gAll$layout$name), select = t:r))
pos2 <- lapply(pos2, "[", 2)

# Drop original panel material in the middle plot
drop <- gAll$layout$name %in% c("panel-1-2", "strip-t-1-2", "axis-b-1-2", "axis-l-2-1")
gAll$grobs[drop] <- NULL
gAll$layout <- gAll$layout[!drop,]

# Add new 'panels' to gAll
gAll <- gtable_add_grob(gAll, panels, t = pos2$t-1, l = pos2$l, b = pos2$t+1,  name = "panels")

# Add new 'axisL' to gAll
gAll <- gtable_add_grob(gAll, axisL, t = pos2$t, l = pos2$l-1, name = "strips")

# Add row above the current strips
gAll <- gtable_add_rows(gAll, gAll$heights[pos2$t-1], pos2$t-2)  

# Add grob, a new strip containing variable name 'PAHs', into the new row
gAll <- gtable_add_grob(gAll, 
  list(rectGrob(gp = gpar(col = NA, fill = "gray85")),
       textGrob("PAHs", gp = gpar(fontsize = 9.6))), 
  t = pos2$t-1, l = pos2$l, name = c("background", "text"))

# Add a small gap between the strips
gAll <- gtable_add_rows(gAll, unit(1/10, "line"), pos2$t-1)

# Probably not needed, but if axisB font size in pMid is different from pAll
gAll$heights[pos2$t + 3] <- gMid$heights[unique(pos1$t) + 1]

# Draw it
grid.newpage()
grid.draw(gAll)

enter image description here




all = structure(list(hydrocarbons = structure(c(21L, 28L, 29L, 30L, 
31L, 12L, 13L, 14L, 15L, 60L, 62L, 63L, 64L, 65L, 6L, 7L, 8L, 
9L, 10L, 16L, 67L, 17L, 18L, 19L, 2L, 3L, 4L, 5L, 32L, 33L, 34L, 
35L, 36L, 37L, 38L, 39L, 40L, 41L, 42L, 43L, 44L, 45L, 46L, 47L, 
48L, 49L, 50L, 51L, 52L, 53L, 54L, 55L, 56L, 57L, 58L, 23L, 24L, 
25L, 26L, 1L, 68L, 11L, 20L, 61L, 59L, 66L, 22L, 27L), .Label = c("Benzene", 
"C", "C1", "C2", "C3", "D", "D1", "D2", "D3", "D4", "Ethylbenzene", 
"F", "F1", "F2", "F3", "FL", "FL1", "FL2", "FL3", "m-Xylene", 
"N", "n-Butylbenzene", "n-C5 (Pentane)", "n-C6 (Hexane)", "n-C7 (Heptane)", 
"n-C9 (Nonane)", "n-Pentylbenzene", "N1", "N2", "N3", "N4", "nC-10", 
"nC-11", "nC-12", "nC-13", "nC-14", "nC-15", "nC-16", "nC-17", 
"nC-18", "nC-19", "nC-20", "nC-21", "nC-22", "nC-23", "nC-24", 
"nC-25", "nC-26", "nC-27", "nC-28", "nC-29", "nC-30", "nC-31", 
"nC-32", "nC-33", "nC-34", "nC-35", "nC-36", "o-Xylene", "P", 
"p-Xylene", "P1", "P2", "P3", "P4", "Propylbenzene", "PY", "Toluene"
), class = "factor"), average = c(6.21, 4.71, 7.6, 16.18, 18.8, 
16.87, 16.64, 18.67, 22.79, 7.97, 26.66, 21.72, 18.99, 66.28, 
8.33, 8.63, 9.57, 20.69, 32.5, 10.37, 10.53, 24.42, 42.52, 51.99, 
74.28, 46.56, 82.85, 114.42, 2.24, 2.24, 4.85, 5.54, 6.81, 5.56, 
5.95, 5.82, 5.7, 6.41, 7.36, 6.24, 6.07, 6.35, 7.32, 6.6, 5.97, 
6.51, 7.57, 8.37, 9.05, 10.27, 11.5, 14.31, 16.96, 20.52, 21.88, 
10.63, 1.74, 9.62, 2.34, 23.51, 18.48, 7.55, 12.53, 15.21, 21.96, 
12.8, 9.33, 6.77), SD = c(4.632774217, 2.43670665, 3.266286228, 
11.00643289, 4.59631824, 7.022165062, 5.721267073, 8.467132345, 
0.988021105, 0.211647391, 16.64819987, 4.416811664, 4.635405486, 
7.706085861, 0.89862145, NA, NA, 3.453922632, 8.191613185, NA, 
NA, 8.886055918, 9.466539232, 15.77786373, 9.560499532, 15.86163409, 
4.854714782, 41.70884318, NA, NA, 1.414267191, 0.089306765, 0.241222891, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 2.215395794, 1.839829721, 
1.972060107, 1.797509743, 3.004883333, 3.503601406, 4.242811665, 
5.087821955, 8.085948386, 10.10105484, 14.1878649, 13.40071226, 
1.715015757, 0.859880844, 4.316473516, 0.044641, 0.631882255, 
2.369137637, 7.171631537, 7.250491275, 1.800247445, 2.184177383, 
15.31136895, 5.486543125, 0.420247353), type = structure(c(2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L), .Label = c("alkanes", "PAHs", "VOCs"), class = "factor"), 
    group = structure(c(6L, 6L, 6L, 6L, 6L, 5L, 5L, 5L, 5L, 7L, 
    7L, 7L, 7L, 7L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 2L, 
    2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = c("", 
    "Chrysenes", "Dibenzothiophenes", "Fluoranthenes", "Fluorenes", 
    "Naphtalenes", "Phenanthrenes"), class = "factor")), .Names = c("hydrocarbons", 
"average", "SD", "type", "group"), class = "data.frame", row.names = c(NA, 
-68L))

Upvotes: 5

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