ggplot2 draw dashed lines of same colour as solid lines belonging to different groups

ggplot2, r

Solution

To add dotted lines you should add 2 `geom_line()` call where you provide y values inside `aes()`. There is no need to put `data=` and `groups=` arguments as they are the same as in `ggplot()` call. `linetype="dotted"` should be placed outside `aes()` call. For the colors you need only one `scale_color_manual()`. To remove dotted line pattern from legend you can override aesthetic using functions `guides()` and `guide_legend()`.

ggplot(data, aes(x = x, y= mean, group = as.factor(data$group), 
                          colour=as.factor(data$group))) + 
  geom_line() + geom_point() + 
  geom_line(aes(y=lower),linetype="dotted") + 
  geom_line(aes(y=upper),linetype="dotted")+
  scale_color_manual(name="Groups",values=c("red", "blue"))+
  guides(colour = guide_legend(override.aes = list(linetype = 1)))

Problem

I am trying to plot 2 solid lines in 2 different colours for each group, but also add dashed lines of the same colour around those lines, then add a legend. For some reason I am having trouble using "dashed" or "dotted", it seems as I am plotting over the dashed lines twice. I am also not getting the legend right, I get the error `Adding another scale for 'colour', which will replace the existing scale`. Can you please help me figure out what I am doing wrong? Here is an example dataset and what I have tried: ``` x <- c(10, 20, 50, 10, 20, 50) mean = c(52.4, 98.2, 97.9, 74.1, 98.1, 97.6) group = c(1, 1, 1, 2,2,2) upper = c(13.64, 89, 86.4, 13.64, 89, 86.4) lower = c(95.4, 99.8, 99.7, 95.4, 99.8, 99.7) data <- data.frame(x=x,y=mean, group, upper, lower) ggplot(data, aes(x = x, y= mean, group = as.factor(data$group), colour=as.factor(data$group))) + geom_line() + geom_point() + geom_line(data=data,aes(x=x, y=lower, group = as.factor(data$group), colour=as.factor(data$group), linetype="dotted")) + geom_line(data=data,aes(x=x, y=upper, group = as.factor(data$group), colour=as.factor(data$group), linetype="dotted")) + scale_color_manual(values=c("red", "blue")) + scale_colour_discrete(name="Groups") ``` I have also tried with `geom_ribbon`, again with no luck for the grouping part… ``` ggplot(data, aes(x = x, y= mean, group = group)) + geom_line() + geom_ribbon(aes(ymin = lower, ymax = upper)) + geom_line(aes(y = mean), colour = "Mean")) + scale_colour_manual(name = "", values = c("Group1", "Group2")) ```

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