Colorize lines in a grouped and facet_wrap ggplot

Question

I have the following data frame:

structure(list(milieu = structure(c(3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L), .Label = c("BUM", 
    "DDR", "ETB", "EXP", "HED", "KON", "MAT", "PER", "PMA", "TRA"
    ), class = "factor"), mycols = structure(c(3L, 1L, 5L, 6L, 2L, 
    4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 
    3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 
    4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 
    3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 
    4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 
    3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 
    4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 
    3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 
    4L, 10L, 8L, 7L, 9L, 3L, 1L, 5L, 6L, 2L, 4L, 10L, 8L, 7L, 9L), .Label = c("#00CCFF", 
    "#00FD03", "#3168FF", "#97CB00", "#98CBF8", "#CCFCCC", "#FB02FE", 
    "#FE9900", "#FF0200", "#FFFD00"), class = "factor"), variable = structure(c(8L, 
    8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 
    7L, 7L, 7L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 11L, 11L, 
    11L, 11L, 11L, 11L, 11L, 11L, 11L, 11L, 14L, 14L, 14L, 14L, 14L, 
    14L, 14L, 14L, 14L, 14L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 10L, 
    10L, 10L, 12L, 12L, 12L, 12L, 12L, 12L, 12L, 12L, 12L, 12L, 3L, 
    3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 
    6L, 6L, 6L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
    2L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 13L, 13L, 13L, 13L, 
    13L, 13L, 13L, 13L, 13L, 13L), .Label = c("Auslaender", "Umweltbelastung", 
    "OEPNV", "Kriminalitaet", "Einr. f. Kinder", "Mangel an Gruenflaechen", 
    "Gaststaette", "Geschaeft", "Bank", "Park", "Hausarzt", "Sportstaette", 
    "Einr. f. Jugendliche", "Einr. F. Aeltere"), class = "factor", scores = structure(c(0.0718023287061849, 
    0.0693420423225302, 0.0753384763664876, 0.0827043835101492, 0.109631516692048, 
    0.0765927537218141, 0.0870322381232645, 0.0515014684350035, 0.0683398169561522, 
    0.0554744519820495, 0.0363337127130046, 0.0463575341160886, 0.0671060291182815, 
    0.102443247236942), .Dim = 14L, .Dimnames = list(c("Geschaeft", 
    "Gaststaette", "Bank", "Hausarzt", "Einr. F. Aeltere", "Park", 
    "Sportstaette", "OEPNV", "Mangel an Gruenflaechen", "Kriminalitaet", 
    "Auslaender", "Umweltbelastung", "Einr. f. Kinder", "Einr. f. Jugendliche"
    )))), value = c(0.0468431771894094, 0.0916666666666667, 0.0654761904761905, 
    0.0905432595573441, 0.0761904761904762, 0.0672097759674134, 0.0869565217391304, 
    0.0650887573964497, 0.0762250453720508, 0.0518234165067179, 0.0855397148676171, 
    0.0604166666666667, 0.0555555555555556, 0.0764587525150905, 0.0895238095238095, 
    0.0712830957230143, 0.075098814229249, 0.0631163708086785, 0.0780399274047187, 
    0.0383877159309021, 0.065173116089613, 0.0854166666666667, 0.0972222222222222, 
    0.0824949698189135, 0.060952380952381, 0.0529531568228106, 0.0731225296442688, 
    0.0828402366863905, 0.0725952813067151, 0.0806142034548944, 0.0712830957230143, 
    0.0833333333333333, 0.0912698412698413, 0.0704225352112676, 0.0628571428571429, 
    0.0672097759674134, 0.106719367588933, 0.0710059171597633, 0.108892921960073, 
    0.0940499040307102, 0.10183299389002, 0.104166666666667, 0.107142857142857, 
    0.100603621730382, 0.12, 0.116089613034623, 0.112648221343874, 
    0.112426035502959, 0.121597096188748, 0.0998080614203455, 0.0855397148676171, 
    0.0666666666666667, 0.0912698412698413, 0.0804828973843058, 0.0704761904761905, 
    0.0672097759674134, 0.0731225296442688, 0.0670611439842209, 0.0834845735027223, 
    0.0806142034548944, 0.0855397148676171, 0.0791666666666667, 0.0952380952380952, 
    0.0824949698189135, 0.0933333333333333, 0.114052953156823, 0.0810276679841897, 
    0.0788954635108481, 0.0780399274047187, 0.0825335892514395, 0.0529531568228106, 
    0.05625, 0.0456349206349206, 0.0583501006036217, 0.0666666666666667, 
    0.0366598778004073, 0.0434782608695652, 0.0571992110453649, 0.0344827586206897, 
    0.0633397312859885, 0.0692464358452139, 0.0645833333333333, 0.0694444444444444, 
    0.0422535211267606, 0.0666666666666667, 0.0692464358452139, 0.0711462450592885, 
    0.0749506903353057, 0.0598911070780399, 0.0959692898272553, 0.0672097759674134, 
    0.0541666666666667, 0.0476190476190476, 0.0422535211267606, 0.0628571428571429, 
    0.0509164969450102, 0.0454545454545455, 0.0532544378698225, 0.058076225045372, 
    0.072936660268714, 0.0244399185336049, 0.04375, 0.0416666666666667, 
    0.0663983903420523, 0.0228571428571429, 0.0509164969450102, 0.0237154150197628, 
    0.0236686390532544, 0.0217785843920145, 0.0441458733205374, 0.0468431771894094, 
    0.0479166666666667, 0.0476190476190476, 0.0402414486921529, 0.0438095238095238, 
    0.0468431771894094, 0.0454545454545455, 0.0512820512820513, 0.0417422867513612, 
    0.0518234165067179, 0.0753564154786151, 0.075, 0.0555555555555556, 
    0.0724346076458753, 0.0533333333333333, 0.0794297352342159, 0.075098814229249, 
    0.0788954635108481, 0.0598911070780399, 0.0460652591170825, 0.122199592668024, 
    0.0875, 0.0892857142857143, 0.0945674044265594, 0.11047619047619, 
    0.109979633401222, 0.0869565217391304, 0.120315581854043, 0.105263157894737, 
    0.0978886756238004), y = structure(c(3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 
    9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 
    1L, 7L, 5L, 4L, 3L, 9L, 8L, 6L, 10L, 2L, 1L, 7L, 5L, 4L), .Label = c("BUM", 
    "DDR", "ETB", "EXP", "HED", "KON", "MAT", "PER", "PMA", "TRA"
    ), class = "factor")), .Names = c("milieu", "mycols", "variable", 
    "value", "y"), row.names = c(NA, -140L), class = "data.frame")

and want to plot it, according to ggplot2 plot table as lines (Thanks Ramnath) with:

ggplot(mdf, aes(x = variable, y = value)) +
  geom_line(data = transform(mdf, milieu = NULL), aes(group = y), colour = 'grey80')+
  geom_line(aes(group = milieu)) +
  scale_colour_manual(value=mdf$mycols) +
  facet_wrap(~milieu) +
  opts(axis.text.x = theme_text(angle=90, hjust=1))

The plot looks so far ok, but I can't set the colors of the lines (right now black) in each group to the according colors in mdf$mycols...

Has someone an idea how I can set the colors in the plot? Thanks for your help! Dominik

Answer 1

Here is how you would do it in this case. You can control the thickness of the dark lines by changing "size" and the lightness of the other lines by changing "alpha". The only purpose of the colors I can see is that you don't need to use a legend and can easily look up the figure to compare different facets.

p1 = ggplot(mdf, aes(x = variable, y = value, colour = mycols)) + 
  geom_line(data = transform(mdf, milieu = NULL), aes(group = y), alpha = 0.5) +   
  geom_line(aes(group = milieu, colour = mycols), size = 1.2) + 
  scale_colour_identity() + 
  facet_wrap(~ milieu) +
  theme_bw() +
  opts(axis.text.x = theme_text(angle=90, hjust=1)) +
  opts(legend.position = 'none')