Not able to add data label in waterfall chart using ggplot2 - r

Question

I am trying to plot waterfall chart using ggplot2. When I am placing the data labels it is not putting in the right place.
Below is the code I am using
dataset <- data.frame(TotalHeadcount = c(-417, -12, 276, -276, 787, 14), Category = LETTERS[1:6])
dataset$SortedCategory <- factor(dataset$`Category`, levels = dataset$`Category`)
dataset$id <- seq_along(dataset$TotalHeadcount)
dataset$type <- ifelse(dataset$TotalHeadcount > 0, "in", "out")
dataset[dataset$SortedCategory %in% c("A", "F"), "type"] <- "net"
dataset$type <- factor(dataset$type, levels = c("out", "in", "net"))
dataset$end <- cumsum(dataset$`TotalHeadcount`)
dataset$end <- c(head(dataset$end, -1), 0)
dataset$start <- c(0, head(dataset$end, -1))
dataset$value <-dataset$`TotalHeadcount`
library(ggplot2)
strwr <- function(str) gsub(" ", "\n", str)
ggplot(dataset, aes(fill = type))+ geom_rect(aes(x = SortedCategory, xmin = id - 0.45, xmax = id + 0.45, ymin = end, ymax = start))+ scale_x_discrete("", breaks = levels(dataset$SortedCategory), labels = strwr(levels(dataset$SortedCategory)))+ theme_bw()+ theme(panel.border = element_blank(), panel.grid.major = element_blank(), axis.line = element_line(colour = "gray"))+guides(fill=FALSE)
And below is the output. I want the data label to be just at the beginning or at the end of the bar.
I am not very expert in R. Just trying to learn. Any help would be really appreciated.
I was following the below blog
https://learnr.wordpress.com/2010/05/10/ggplot2-waterfall-charts/
but somehow when I write the same code in geom_text it gives me an error. Could be a syntax related issue.

Answer 1

Here is an approach with ggplot.
First the data:
df1 <- data.frame(z = c(-417, -12, 276, -276, 787, 14),
b = LETTERS[1:6])
library(tidyverse)
Calculate the cumsum and the lag of the cumsum for geom_rect coords
df1 %>%
mutate(val = cumsum(z),
lag = c(0, lag(val)[-1]),
b1 = as.numeric(b)) -> df1
ggplot(df1)+
geom_rect(aes(xmin = b1 - 0.45,
xmax = b1 + 0.45, ymin = lag, ymax = val)) +
geom_text(aes(x = b1, y = val, label = val), #or `label = z`
vjust = ifelse(df1$val < df1$lag, -0.2, 1)) + #geom_text vjust depends on the direction of the value
scale_x_continuous(breaks = 1:6, labels = df1$b)
an easier way, but I think the labels position can not be changed at this moment but it is planned:
rect_text_labels_anchor (character) How should rect_text_labels be
positioned? In future releases, we might have support for north or
south anchors, or for directed positioning (negative down, positive
up) etc. For now, only centre is supported.
library(waterfalls)
df1 <- data.frame(z = c(-417, -12, 276, -276, 787, 14),
b = LETTERS[1:6])
you could also color it the same way in ggplot:
df1 %>%
mutate(val = cumsum(z),
lag = c(0, lag(val)[-1]),
b1 = as.numeric(b),
color = ifelse(val <lag, "down", "up")) -> df1
ggplot(df1)+
geom_rect(aes(xmin = b1 - 0.45,
xmax = b1 + 0.45, ymin = lag, ymax = val, fill = color)) +
geom_text(aes(x = b1, y = val, label = z),
vjust = ifelse(df1$val < df1$lag, -0.2, 1)) +
scale_x_continuous(breaks = 1:6, labels = df1$b)
EDIT: answers to the questions in comments.
Filled waterfall:
df1 <- data.frame(z = c(-417, -12, 276, -276, 787, 14),
b = LETTERS[1:6],
group = rep(c("AB", "CD", "EF"), each = 2))
df1 %>%
mutate(val = cumsum(z),
lag = c(0, lag(val)[-1]),
b1 = as.numeric(b),
g1 = as.numeric(group)) -> df1
ggplot(df1)+
geom_rect(aes(xmin = g1 - 0.45,
xmax = g1 + 0.45, ymin = lag, ymax = val, fill = b)) +
geom_text(aes(x = g1, y = val, label = z),
vjust = ifelse(df1$val < df1$lag, -0.2, 1)) +
scale_x_continuous(breaks = 1:3, labels = unique(df1$group))
To answer what went wrong with your geom_text code I would need to see it. Other then that your code works, but it over-complicates things. I advise you to learn a bit of tidyverse functions, data manipulation will be much cleaner then.
One more note, adding back-ticks:
dataset$`TotalHeadcount`
is not necessary when your column names do not contain special characters:
dataset$TotalHeadcount
EDIT2: to change to order on the x axis you would first change the levels of the grouping factor and then do the calculation and plotting:
df1 <- data.frame(z = c(-417, -12, 276, -276, 787, 14),
b = LETTERS[1:6],
group = rep(c("AB", "CD", "EF"), each = 2))
df1 %>%
mutate(group = factor(group, levels = c("AB", "EF", "CD"))) %>%
arrange(group) %>%
mutate(val = cumsum(z),
lag = c(0, lag(val)[-1]),
b1 = as.numeric(b),
g1 = as.numeric(group)) -> df1
ggplot(df1)+
geom_rect(aes(xmin = g1 - 0.45,
xmax = g1 + 0.45, ymin = lag, ymax = val, fill = b)) +
geom_text(aes(x = g1, y = val, label = z),
vjust = ifelse(df1$val < df1$lag, -0.2, 1)) +
scale_x_continuous(breaks = 1:3, labels = unique(df1$group))