从ggplot2线型和颜色图表的图例中省略线型

Question

I have a problem with the legend of the graph that uses both line type and line color. I want for the legend to show just the two colors I used and omit line type from the legend. I plan to annotate the lines so the legend is not needed. I couldn't find a solution to this problem.

Here's the head of the dataset I used. Variable StateAndGender has 4 different values, each of the two countries by two genders.

head(le) 
    Age StateAndGender      Value V4
1    <1            EuM 0.03774679  1
2   4-5            EuM 0.02771025  2
3   5-9            EuM 0.03086298  3
4 10-14            EuM 0.03001608  4
5 15-19            EuM 0.04380364  5
6 20-24            EuM 0.05579602  6

When I execute the code below I get:

le.chart <- ggplot(data=le, aes(x=reorder(Age, V4), y=Value,
group=StateAndGender,linetype=StateAndGender, col=StateAndGender)) 
le.chart +
geom_line(size=1.25) +
coord_fixed(ratio=0.5)+
theme(text=element_text(size=12, family="Times New Roman"),
        axis.text=element_text(size=10),
        axis.title=element_text(size=11))+
scale_linetype_manual(values=c(1,8,1,8), guide=FALSE) +
scale_color_manual(values = c("#636363","#636363","#BDBDBD","#BDBDBD"),
                     labels=c("Country 1 / Italic text "," ", "Country / Italic text"),
                     guide=guide_legend(title = "Легенда"))+
annotate("text", label = "Males / ITALIC TEXT ", x = 13, y=18, family="Times New Roman")+
annotate("text", label = "Females / ITALIC TEXT ", x = 16, y =1.25, family="Times New Roman")+
xlab(NULL)+
ylab(NULL)+
guides(linetype=FALSE)

I tried splitting the StateAndGender variable into two and setting group=State, linetype=State, col=Gender, but I got the error:

"Error: geom_path: If you are using dotted or dashed lines, colour, size and linetype must be constant over the line"

If what I want can't be done, is there a way to manually define every aspect of the legend, completely separating it from the data?

By the way I have a separate problem with using annotation with partly italic text annotations. expression(italic("Italic text")) doesn't seem to be working (it doesn't display text at all)

Answer 1

Try removing the linetype=StateAndGender from the aes(...) and put it outside of it in the overall ggplot(..) function or in the geom_line(...) function. It'll look like this:

le.chart <- ggplot(data=le, aes(x=reorder(Age, V4), y=Value,
group=StateAndGender, col=StateAndGender),linetype=StateAndGender) 
le.chart + . . .