I am calling the ggplot function
ggplot(data,aes(x,y,fill=category)+geom_bar(stat="identity")
The result is a barplot with bars filled by various colours corresponding to category. However the ordering of the colours is not consistent from bar to bar. Say there is pink, green and blue. Some bars go pink,green,blue from bottom to top and some go green,pink,blue. I don't see any obvious pattern.
How are these orderings chosen? How can I change it? At the very least, how can I make ggplot choose a consistent ordering?
The class of (x,y and category) are (integer,numeric and factor) respectively. If I make category an ordered factor, it does not change this behavior.
Anyone know how to fix this?
Reproducible example:
dput(data)
structure(list(mon = c(9L, 10L, 11L, 10L, 8L, 7L, 7L, 11L, 9L,
10L, 12L, 11L, 7L, 12L, 8L, 12L, 9L, 7L, 9L, 10L, 10L, 8L, 12L,
7L, 11L, 10L, 8L, 7L, 11L, 12L, 12L, 9L, 9L, 7L, 7L, 12L, 12L,
9L, 9L, 8L), gclass = structure(c(9L, 1L, 8L, 6L, 4L, 4L, 3L,
6L, 2L, 4L, 1L, 1L, 5L, 7L, 1L, 6L, 8L, 6L, 4L, 7L, 8L, 7L, 9L,
8L, 3L, 5L, 9L, 2L, 7L, 3L, 5L, 5L, 7L, 7L, 9L, 2L, 4L, 1L, 3L,
8L), .Label = c("Down-Down", "Down-Stable", "Down-Up", "Stable-Down",
"Stable-Stable", "Stable-Up", "Up-Down", "Up-Stable", "Up-Up"
), class = c("ordered", "factor")), NG = c(222614.67, 9998.17,
351162.2, 37357.95, 4140.48, 1878.57, 553.86, 40012.25, 766.52,
15733.36, 90676.2, 45000.29, 0, 375699.84, 2424.21, 93094.21,
120547.69, 291.33, 1536.38, 167352.21, 160347.01, 26851.47, 725689.06,
4500.55, 10644.54, 75132.98, 42676.41, 267.65, 392277.64, 33854.26,
384754.67, 7195.93, 88974.2, 20665.79, 7185.69, 45059.64, 60576.96,
3564.53, 1262.39, 9394.15)), .Names = c("mon", "gclass", "NG"
), row.names = c(NA, -40L), class = "data.frame")
ggplot(data,aes(mon,NG,fill=gclass))+geom_bar(stat="identity")
To reorder the boxplot we will use reorder() function of ggplot2. By default, ggplot2 orders the groups in alphabetical order. But for better visualization of data sometimes we need to reorder them in increasing and decreasing order. This is where the reorder() function comes into play.
Generally, fill defines the colour with which a geom is filled, whereas colour defines the colour with which a geom is outlined (the shape's "stroke", to use Photoshop language). But unless you're using those special shapes, if you use a point, give it a colour , not a fill (because most points don't have one).
To reorder bars manually, you have to pass stat=”identity” in the geom_bar() function.
R barplot() – Set Colors for Bars in Bar Plot To set colors for bars in Bar Plot drawn using barplot() function, pass the required color value(s) for col parameter in the function call. col parameter can accept a single value for color, or a vector of color values to set color(s) for bars in the bar plot.
Starting in ggplot2_2.0.0, the order
aesthetic is no longer available. To get a graph with the stacks ordered by fill color, you can simply order the dataset by the grouping variable you want to order by.
I often use arrange
from dplyr for this. Here I'm ordering the dataset by the fill
factor within the ggplot
call rather than creating an ordered dataset but either will work fine.
library(dplyr)
ggplot(arrange(data, gclass), aes(mon, NG, fill = gclass)) +
geom_bar(stat = "identity")
This is easily done in base R, of course, using the classic order
with the extract brackets:
ggplot(data[order(data$gclass), ], aes(mon, NG, fill = gclass)) +
geom_bar(stat = "identity")
With the resulting plot in both cases now in the desired order:
ggplot2_2.2.0 update
In ggplot_2.2.0, fill order is based on the order of the factor levels. The default order will plot the first level at the top of the stack instead of the bottom.
If you want the first level at the bottom of the stack you can use reverse = TRUE
in position_stack
. Note you can also use geom_col
as shortcut for geom_bar(stat = "identity")
.
ggplot(data, aes(mon, NG, fill = gclass)) +
geom_col(position = position_stack(reverse = TRUE))
You need to specify the order
aesthetic as well.
ggplot(data,aes(mon,NG,fill=gclass,order=gclass))+
geom_bar(stat="identity")
This may or may not be a bug.
To order, you must use the levels
parameter and inform the order. Like this:
data$gclass
(data$gclass2 <- factor(data$gclass,levels=sample(levels(data$gclass)))) # Look the difference in the factors order
ggplot(data,aes(mon,NG,fill=gclass2))+geom_bar(stat="identity")
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