White space between tiles in heatplot ggplot

问题:

I have this heatplot that I've generated using ggplot2.

What I would like to do is to add white space between the variables listed in capital letters and the variables listed in lower case letters so as to separate these two categories. I still want the tiles to be of equal width.

The code I've used to generate the plot is:

ggplot(mockdata, aes(variable, Measurement)) + 
  geom_tile(aes(fill = mockdata$plotval), colour = "dark red")  + scale_fill_gradient2(limits=c(-20, 20),high = "firebrick3", low = "dodgerblue4") + 
  theme_minimal() + theme(axis.text.x=element_text(size=28, angle=90), axis.text.y=element_text(size=28)) + 
  labs(title="", x="", y="", fill="") 

And my data looks as follows:

> head(mockdata)    Measurement variable         Pval       effect
> direction    plotval category 21          20        A 4.511987e+04
> -0.004892941        -1 -4.6543678 Measured 22          19        A 3.436853e-08  0.054344854         1  7.4638390 Measured 23          18        A 1.465755e+00  0.355139910         1 -0.1660613 Measured 24         
> 17        A 7.006222e-04 -0.079390247        -1  3.1545161 Measured 25
> 16        A 4.705051e-04 -0.017708611        -1  3.3274357 Measured 26
> 15        A 2.301113e+03 -0.022934623        -1 -3.3619379 Measured

PS. While it is strictly another question, I would also like to edit the legend so that it ranges simply from 0-20 and is split in two vertically, showing on one side the red gradient and the blue gradient on the other.

Thank you very much for your help.

Edit: dput output as requested

    dput(mockdata)
structure(list(Measurement = structure(c(20L, 19L, 18L, 17L, 
16L, 15L, 14L, 13L, 12L, 11L, 10L, 9L, 8L, 7L, 6L, 5L, 4L, 3L, 
2L, 1L, 20L, 19L, 18L, 17L, 16L, 15L, 14L, 13L, 12L, 11L, 10L, 
9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L, 20L, 19L, 18L, 17L, 16L, 
15L, 14L, 13L, 12L, 11L, 10L, 9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 
1L, 20L, 19L, 18L, 17L, 16L, 15L, 14L, 13L, 12L, 11L, 10L, 9L, 
8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L, 20L, 19L, 18L, 17L, 16L, 15L, 
14L, 13L, 12L, 11L, 10L, 9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L, 
20L, 19L, 18L, 17L, 16L, 15L, 14L, 13L, 12L, 11L, 10L, 9L, 8L, 
7L, 6L, 5L, 4L, 3L, 2L, 1L, 20L, 19L, 18L, 17L, 16L, 15L, 14L, 
13L, 12L, 11L, 10L, 9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L, 20L, 
19L, 18L, 17L, 16L, 15L, 14L, 13L, 12L, 11L, 10L, 9L, 8L, 7L, 
6L, 5L, 4L, 3L, 2L, 1L, 20L, 19L, 18L, 17L, 16L, 15L, 14L, 13L, 
12L, 11L, 10L, 9L, 8L, 7L, 6L, 5L, 4L, 3L, 2L, 1L), .Label = c("1", 
"2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", 
"14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", 
"25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", 
"36", "37", "38", "39", "40"), class = "factor"), variable = structure(c(1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 5L, 
5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 
5L, 5L, 5L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 
6L, 6L, 6L, 6L, 6L, 6L, 6L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 
7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 8L, 8L, 8L, 8L, 8L, 
8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 9L, 
9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 
9L, 9L, 9L), .Label = c("A", "B", "C", "a", "b", "c", "d", "e", 
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    "Measured", "Measured", "Measured", "Measured", "Measured", 
    "Measured", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived", "Derived", "Derived", "Derived", "Derived", "Derived", 
    "Derived")), .Names = c("Measurement", "variable", "Pval", 
"effect", "direction", "plotval", "category"), row.names = c(21L, 
22L, 23L, 24L, 25L, 26L, 27L, 28L, 29L, 30L, 31L, 32L, 33L, 34L, 
35L, 36L, 37L, 38L, 39L, 40L, 61L, 62L, 63L, 64L, 65L, 66L, 67L, 
68L, 69L, 70L, 71L, 72L, 73L, 74L, 75L, 76L, 77L, 78L, 79L, 80L, 
101L, 102L, 103L, 104L, 105L, 106L, 107L, 108L, 109L, 110L, 111L, 
112L, 113L, 114L, 115L, 116L, 117L, 118L, 119L, 120L, 141L, 142L, 
143L, 144L, 145L, 146L, 147L, 148L, 149L, 150L, 151L, 152L, 153L, 
154L, 155L, 156L, 157L, 158L, 159L, 160L, 181L, 182L, 183L, 184L, 
185L, 186L, 187L, 188L, 189L, 190L, 191L, 192L, 193L, 194L, 195L, 
196L, 197L, 198L, 199L, 200L, 221L, 222L, 223L, 224L, 225L, 226L, 
227L, 228L, 229L, 230L, 231L, 232L, 233L, 234L, 235L, 236L, 237L, 
238L, 239L, 240L, 261L, 262L, 263L, 264L, 265L, 266L, 267L, 268L, 
269L, 270L, 271L, 272L, 273L, 274L, 275L, 276L, 277L, 278L, 279L, 
280L, 301L, 302L, 303L, 304L, 305L, 306L, 307L, 308L, 309L, 310L, 
311L, 312L, 313L, 314L, 315L, 316L, 317L, 318L, 319L, 320L, 341L, 
342L, 343L, 344L, 345L, 346L, 347L, 348L, 349L, 350L, 351L, 352L, 
353L, 354L, 355L, 356L, 357L, 358L, 359L, 360L), class = "data.frame")

回答1:

Option 1

Use facets

mockdata$type = ifelse(mockdata$variable %in% LETTERS[1:3], "1", "2")

ggplot(mockdata) + 
  facet_wrap(~ type, scales='free_x') +
  geom_tile(aes(variable, Measurement, fill = mockdata$plotval), colour = "dark red")  + 
  scale_fill_gradient2(limits=c(-20, 20),high = "firebrick3", low = "dodgerblue4") + 
  theme_minimal() + 
  theme(axis.text.x=element_text(size=28, angle=90), axis.text.y=element_text(size=28)) + 
  labs(title="", x="", y="", fill="") 

Although this is not quite perfect, because dropping the unused x-axis categories from each facet requires specifying scales='free_x' - which unfortunately does not keep the boxes the same width in each facet.

Option2

To remedy this we can also set space="free_x" in facet_grid. Which I think gives what you are looking for:

ggplot(mockdata) + 
  facet_grid(~ type, scales='free_x', space="free_x") +
  geom_tile(aes(variable, Measurement, fill = mockdata$plotval), colour = "dark red")  + 
  scale_fill_gradient2(limits=c(-20, 20),high = "firebrick3", low = "dodgerblue4") + 
  theme_minimal() + 
  theme(axis.text.x=element_text(size=28, angle=90), axis.text.y=element_text(size=28)) + 
  labs(title="", x="", y="", fill="") 

Option 3

An alternative solution is to create separate plots for each category, and arrange them together. Here I put them together using cowplot::plot_grid, which allows us to set the relative widths how we want them (although you may need to tweak the rel_widths values a bit to get it just right):

library(cowplot)
p1 <- ggplot(mockdata[which(mockdata$type=="1"),]) + 
  geom_tile(aes(variable, Measurement, fill = plotval), colour = "dark red")  + 
  scale_fill_gradient2(limits=c(-20, 20), high = "firebrick3", low = "dodgerblue4") + 
  theme_minimal() + 
  theme(axis.text.x=element_text(size=28, angle=90), axis.text.y=element_text(size=28),
        legend.position="none") + 
  labs(title="", x="", y="", fill="") 

p2 <- ggplot(mockdata[which(mockdata$type=="2"),]) + 
  geom_tile(aes(variable, Measurement, fill = plotval), colour = "dark red")  + 
  scale_fill_gradient2(limits=c(-20, 20),high = "firebrick3", low = "dodgerblue4") + 
  theme_minimal() + 
  theme(axis.text.x=element_text(size=28, angle=90), axis.text.y=element_blank()) + 
  labs(title="", x="", y="", fill="") 

plot_grid(p1,p2, nrow = 1,  rel_widths = c(1,2))

Option 4

You can create an extra factor level in the data, which lies between the columns you want to separate, and then plot tiles for that column in white.

mockdata = rbind(mockdata, 
                 data.frame(Measurement=1:20, 
                            variable="", 
                            Pval = NA,
                            effect = NA,
                            direction = NA,
                            plotval = 0,
                            category = "Measured"))
mockdata$variable = factor(mockdata$variable, levels = c("A", "B", "C", "", "a", "b", "c", "d", "e","f"))

ggplot(mockdata, aes(variable, Measurement)) + 
  geom_tile(fill = NA, colour = NA)  + 
  geom_tile(data = mockdata[which(mockdata$variable==""),], fill = "white", colour = "white")  + 
  geom_tile(data = mockdata[which(mockdata$variable!=""),], aes(fill = plotval), colour = "dark red")  + 
  scale_fill_gradient2(limits=c(-20, 20),high = "firebrick3", low = "dodgerblue4") + 
  theme_minimal() + 
  theme(axis.text.x=element_text(size=28, angle=90), axis.text.y=element_text(size=28)) + 
  labs(title="", x="", y="", fill="")