Line plot with gray and black dotted lines

Question

With the ggplot2 R package I made a line plot with 6 colored lines (referred to 6 levels of a factor), and I would like to change it in black and white, making 3 BLACK solid, dashed and dotted lines plus 3 GREY solid, dashed and dotted lines. I try with scale_linetype_manual() and scale_color_grey() but I'm not able to mix the grey and black dotted lines.

Here the code of the scale grey option:

ggplot() + 
  geom_line(data = f[!is.na(f$fr),], aes(x=date2, y=fr, colour=locality, group=locality), 
            size = 1.0) + 
  scale_color_grey(start = 0, end = 0.9, guide="legend", name="Locality", 
                   labels=c("a","b","c","d","e","f")) + 
  xlab("") + 
  ylab("") + 
  theme_bw() +
  theme(legend.position = "top", panel.background = element_rect(fill = "white"), 
        panel.grid.major = element_line(colour = "white"), 
        axis.text.x=element_text(angle=90,hjust=1,vjust=0.5)) + 
  facet_grid(.~year)

while this is the code with dotted lines:

ggplot() + 
  geom_line(data = f[!is.na(f$fr),], aes(x=date2, y=fr, linetype=locality, group=locality), 
            size = 1.0) + 
  scale_linetype_manual(name="Locality", 
                        values=c("solid", "dashed", "dotted", "dotdash", "longdash", "twodash"), 
                        labels=c("a","b","c","d","e","f")) +
  xlab("") + 
  ylab("") + 
  theme_bw()+ 
  theme(legend.position = "top", panel.background = element_rect(fill = "white"), 
        panel.grid.major = element_line(colour = "white"), 
        axis.text.x=element_text(angle=90,hjust=1,vjust=0.5)) +
  facet_grid(.~year)

so.. Someone can help me to create this same plot with one solid black line, one dashed black line, one dotted black line, one solid grey line etc.?

Thank you. I try to add it in the last code and it doesn't work... this is the output: Error in scale$palette(n) : argument "values" is missing, with no default — Elena
did you try scale_colour_manual(values=c("black", "grey", "black", "grey", "black", "grey")) — MLavoie
yes, I try also "grey50", "grey"80", ... but still don't work. I think that it is possible to connect every line with its colour in the same "scale_linetype_manual()" command, but I don't know how... thank you — Elena

Axeman Axeman · Accepted Answer · 2015-12-01T13:37:33

Map to both colour and linetype, and set manual scales.

d <- data.frame(locality = rep(letters[1:6], each = 2),
            x = 1:2,
            y = rep(1:6, each = 2))

ggplot(d, aes(x = x, y = y,colour = locality, linetype = locality)) + 
  geom_line() +
  theme_bw() +
  scale_color_manual(name = "Locality",
                     values = c('black', 'black', 'black', 'grey', 'grey', 'grey'),
                     labels = c("a","b","c","d","e","f")) +
  scale_linetype_manual(name = "Locality", 
                        values = c("solid", "dashed", "dotted", "solid", "dashed", "dotted"), 
                        labels = c("a","b","c","d","e","f"))

Line plot with gray and black dotted lines

2 Answers