R: connect points on a graph (ggplot2) - r

Question

Suppose I have data in the following form:
library(ggplot2)
Data <- data.frame(
"ID" = c("ABC111", "ABC111", "ABC111", "ABC111", "ABC112", "ABC112", "ABC112", "ABC113", "ABC113", "ABC114", "ABC115"),
"color" = c("red", "red", "red", "red", "blue", "blue", "blue", "green", "green", "black", "yellow"),
"start_date" = c("2005/01/01", "2006/01/01", "2007/01/01", "2008/01/01", "2009/01/01", "2010/01/01", "2011/01/01", "2012/01/01", "2013/01/01", "2014/01/01", "2015/01/01"),
"end_date" = c("2005/09/01", "2006/06/01", "2007/04/01", "2008/05/07", "2009/06/01", "2010/10/01", "2011/12/12", "2013/05/01", "2013/06/08", "2015/01/01", "2016/08/09")
)
Data$ID = as.factor(Data$ID)
Data$color = as.factor(Data$color)
Now what I want to do is for each row, plot the start_date and the end_date ... and then connect them with a straight line. I believe this can be done with geom_line() in ggplot2.
I want something that looks like this:
I tried using the following code:
q <- qplot(start_date, end_date, data=Data)
q <- q + geom_line(aes(group = ID))
q
But the graph looks completely different than what I expected.
Can anyone please show me what I am doing wrong?
Thanks

Answer 1

Does the following work for you?
ggplot(data = Data, aes(start_date, end_date, color = ID))+
geom_line(aes(group = ID))+
geom_point()
or maybe geom_segment ?
# Adding x and y coordinates for geom_segment
Data$x <- as.character(as.Date(Data$start_date) + (as.Date(Data$end_date) - as.Date(Data$start_date)))
Data$y <- 1:nrow(Data)
ggplot(data = Data, aes(x, y, colour = ID))+
geom_segment(aes(xend = start_date, yend = end_date))

Answer 2

Here's a solution using the tidyverse package. I used the number of each row in the original data as the y-axis values in the plot. As these values are meaningless, I removed the y-axis title, labels and ticks from the plot.
library(tidyverse)
Data %>%
# Number each row in its order of appearance,
# save this numbers in a new column named order
rowid_to_column("order") %>%
# Change data from wide to long format
pivot_longer(cols = c(start_date, end_date),
names_to = "date_type",
values_to = "date") %>%
# Ggplot, use date as x, order as y, ID as col and order as group
ggplot(aes(x = date,
y = order,
col = ID,
group = order)) +
# Draw points
geom_point()+
# Draw lines
geom_line() +
# Maybe you want to remove the y axis title, text and ticks
theme(axis.title.y = element_blank(),
axis.text.y = element_blank(),
axis.ticks.y = element_blank(),
# I added a vertical format to the x axis labels
# it might easier to read this way
axis.text.x = element_text(angle = 90, vjust = 0.5))