How can I get my area plot to stack using ggplot? - r

Question

I am trying to get my cumulative area plot to stack using the code below, which is based on http://dantalus.github.io/2015/08/16/step-plots/. I have added in position=stack, however the plot still overlaps.
The aim of what I am trying to achieve is to show the cumulative number of publications each year within a given period. So, as an example, in 1940 there may be one publication, the following year there may be 2 more, bringing the cumulative total to 3.
What would be the best way to get the areas to stack on top of each other?
How can the order be controlled? Would I need to use arrange() to order TERM2?
ggplot(data=working, aes(x=Year, color=TERM2, fill=TERM2)) +
stat_bin(data = subset(working, TERM2=="A"), bins=80, aes(y=cumsum(..count..)),geom="area", position="stack", alpha=0.1) +
stat_bin(data = subset(working, TERM2=="B"), bins=80, aes(y=cumsum(..count..)),geom="area", position="stack",alpha=0.1) +
stat_bin(data = subset(working, TERM2=="Both"),bins=80, aes(y=cumsum(..count..)),geom="area", position="stack", alpha=0.1) +
ylab("Total Number") + xlim(1940,2020) + ggtitle("Cumulative number by measurement method")
What I am currently getting:
Example of what I am trying to achieve:
The following chart was created in Excel using the same data which is exactly what I am looking to achieve in R.
My Data:
Example of how my data is currently structured:
Year TERM2
1944 A
1959 B
1966 A
1968 B
1968 A
1970 A
1971 B
1971 B
1971 A
1971 A
1971 Both
1971 Both
1971 Both
1972 A
1972 Both
1972 Both
1973 B
1973 A
1974 A
1974 A
'data.frame': 803 obs. of 6 variables:
$ Year : int 1944 1959 1966 1968 1968 1970 1971 1971 1971 1971 ...
$ TERM2 : Factor w/ 3 levels "B","A","Both": 2 1 2 1 2 2 1 1 2 2 ...
Changes based on user127649's suggestions
This is the plot after user127649's suggestions, which is close to what I would expect except I am looking for it to start at 0 and end at 803 (total number of publications).
ggplot(data=working, aes(x=Year, color=TERM2, fill=TERM2)) +
stat_bin(bins=80, aes(y=cumsum(..count..)), geom="area", alpha=0.1) +
ylab("Total Number") + xlim(1940,2020) + ggtitle("Cumulative number by measurement method")

Answer 1

I think there were two issues.
When You use stat_bin() in three separate layers, each effectively has it’s own independent data set. This will give the correct count, but (and this is a guess really) I think being in three separate layers means you can’t stack them.
If you use stat_bin() on all the layers I think stat = '..count..' performs cumsum() on the data as a whole.
I don’t know whether this is the best approach or not, but I think it’s what you’re after.
Data
The data are grouped and cumsum() is used on each group separately.
library(tidyverse)
working <- working %>%
count(Year, TERM2) %>%
spread(TERM2, n, fill = 0) %>%
mutate_at(vars('A', 'B', 'Both'), cumsum) %>%
gather(TERM2, N, -Year, factor_key = T) #%>%
# mutate(TERM2 = ordered(TERM2, levels = rev(levels(TERM2))))
Plot
This code will produce the first plot below. If you prefer the look of the second plot, you can un-comment the last line of the data manipulation chunk.
ggplot(working, aes(Year, N, fill = TERM2)) +
geom_area(position = 'stack') +
ylab("Total Number")
Result