I have spent hours looking in the documentation and on StackOverflow, but no solution seems to solve my problem. When using ggplot
I can't get the right text in the legend, even though it's in my dataframe. I have tried scale_colour_manual
, scale_fill_manual
with different values for labels=
such as c("T999", "T888")", "cols"
.
Here is my code:
T999 <- runif(10, 100, 200)
T888 <- runif(10, 200, 300)
TY <- runif(10, 20, 30)
df <- data.frame(T999, T888, TY)
ggplot(data = df, aes(x=T999, y=TY, pointtype="T999")) +
geom_point(size = 15, colour = "darkblue") +
geom_point(data = df, aes(x=T888, y=TY), colour = 'red', size = 10 ) +
theme(axis.text.x = element_text(size = 20), axis.title.x =element_text(size = 20), axis.text.y = element_text(size = 20)) +
xlab("Txxx") + ylab("TY [°C]") + labs(title="temperatures", size = 15) +
scale_colour_manual(labels = c("T999", "T888"), values = c("darkblue", "red")) + theme(legend.position="topright")
Help would be very appreciated!
The legend titles can be labeled by specific aesthetic.
This can be achieved using the guides()
or labs()
functions from ggplot2
(more here and here). It allows you to add guide/legend properties using the aesthetic mapping.
Here's an example using the mtcars
data set and labs()
:
ggplot(mtcars, aes(x=mpg, y=disp, size=hp, col=as.factor(cyl), shape=as.factor(gear))) +
geom_point() +
labs(x="miles per gallon", y="displacement", size="horsepower",
col="# of cylinders", shape="# of gears")
Answering the OP's question using guides()
:
# transforming the data from wide to long
require(reshape2)
dfm <- melt(df, id="TY")
# creating a scatterplot
ggplot(data = dfm, aes(x=TY, y=value, color=variable)) +
geom_point(size=5) +
labs(title="Temperatures\n", x="TY [°C]", y="Txxx") +
scale_color_manual(labels = c("T999", "T888"), values = c("blue", "red")) +
theme_bw() +
guides(color=guide_legend("my title")) # add guide properties by aesthetic
Source: Stackoverflow.com