Background
In Germany, there are 16 federal states, ten of which belonged to West Germany, six of which belonged to East Germany. In some respects, for example mortality rates of certain cancers, there are persistent differences between the ten former western states and the six former eastern ones. There are also differences among the states within the respective groups.
To show the differences among the states, it can make a certain amount of sense to plot data, for example age-standardized breast cancer mortality by year, from each state. A plot with 16 lines is not always a good choice, and I don't want to open up a discussion about that. Sometimes the powers that be say that's how it has to be.
The problem
Differentiating among 16 lines on a plot can be difficult. To do so, I usually use a combination of colors from the RColorBrewer
package (the first ten colors of Set3
plus the first six colors of that palette again, corresponding to the ten former west and six former east states) and line types (one line type for east, one for west). Using the lattice
package, a plot of age-standardized breast cancer mortality rates from 1998-2010 by state could look like this:
The question
I would like to do a similar plot using ggplot
, but I haven't figured out how to combine the colors and the line types in the legend. So far, I've gotten this far:
If it is possible to combine colors and line types in ggplot
legends, how does one go about doing it?
Here's the code to create the data frame and the plots:
mort3 <- structure(list(State = structure(c(8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L, 8L, 9L, 11L, 12L, 4L, 2L, 6L, 13L, 3L, 5L, 7L, 10L, 14L, 15L, 1L, 16L), class = "factor", .Label = c("SH", "HH", "NI", "HB", "NW", "HE", "RP", "BW", "BY", "SL", "BE", "BB", "MV", "SN", "ST", "TH")), BCmort = c(16.5, 16.6, 15, 14.4, 13.5, 17.1, 15.8, 16.3, 18.3, 16.8, 17, 18.1, 13.1, 15.1, 18.8, 13.1, 16.4, 16.1, 15.8, 12.8, 16.3, 19.2, 16.8, 13, 17.9, 17, 19.4, 19.4, 13.1, 13.8, 18.1, 13.8, 15.9, 17.3, 17.5, 13.7, 17.4, 17.5, 16.7, 15.5, 18.1, 18, 20.1, 19.1, 11.8, 14.6, 18.2, 13.4, 16.8, 17.5, 15.6, 14.1, 13.9, 18.2, 17.1, 15.2, 18.1, 16.6, 19.3, 18.6, 13.1, 14.6, 19.6, 12.4, 16.6, 17.8, 17.5, 14.3, 20.5, 19.2, 19, 12.6, 19.5, 17.8, 19.2, 21, 14.4, 13.4, 19.8, 14, 17.5, 18.9, 16.4, 14.7, 17.7, 20.1, 18.5, 14.5, 19.1, 19.2, 20.1, 19.7, 14.2, 16.2, 17.9, 12.6, 18, 18.7, 17.7, 16.5, 16.6, 20.3, 18.1, 15.2, 19, 20, 19.8, 21.3, 13.8, 14.8, 20.4, 14.8, 18.2, 18.7, 16.9, 16.2, 20.2, 20.4, 18.5, 14, 20.2, 18.7, 20.3, 17.7, 14.4, 14.5, 21.7, 13.7, 18.3, 19.7, 17.8, 16.5, 20.2, 21.7, 18.8, 16.7, 20.4, 20, 19.6, 22.9, 15.2, 14.9, 21.7, 14.6, 18.3, 19.7, 17, 16.7, 22.9, 16.2, 19.6, 15.9, 20.3, 19.9, 18.9, 21.8, 14.9, 18, 21.4, 16.1, 19.6, 19.2, 19.1, 16.7, 20, 18.2, 20.5, 15.5, 20.5, 21.1, 21.3, 23.8, 15.8, 15.3, 21.3, 15.7, 19.6, 20.3, 19.2, 17.4, 18.1, 23.1, 20.6, 16.2, 21.5, 20.3, 21.4, 20.8, 16.1, 15.8, 22.1, 14.5, 20, 20.2, 19, 18.7, 23.1, 21.8, 19.4, 17.4, 20.9, 20.5, 20.4, 23.2, 16.3, 17.6, 23.1, 16.5), year = c(2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2010, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2009, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2008, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2007, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2006, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2004, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2003, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2002, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2001, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 2000, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1999, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998, 1998), eastWest = structure(c(1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 2L, 1L, 2L), .Label = c("west", "east"), class = "factor")), .Names = c("State", "BCmort", "year", "eastWest"), class = "data.frame", row.names = c(NA, -208L)) colVec<-c(brewer.pal(10,"Set3"),brewer.pal(6,"Set3")) ltyVec<-rep(c("solid","dashed"),c(10,6)) ggplot(mort3, aes(x = year, y = BCmort, col = State, lty = eastWest)) + geom_line(lwd = 1) + scale_linetype_manual(values = c(west = "solid", east = "dashed")) + scale_color_manual(values = c(brewer.pal(10, "Set3"), brewer.pal(6, "Set3"))) + opts(title = "BC mortality") xyplot(BCmort ~ year, data = mort3, groups = State, lty = ltyVec, type = "l", col = colVec, lwd = 2, key = list(lines = list(lty = ltyVec, col = colVec, lwd = 2), text = list(levels(mort3$State)), columns = 1, space = "right", title = "State"), grid = TRUE, main = "BC mortality")
To change the linetype for geom_vline, we can use linetype argument in geom_vline function of ggplot2 package. There are mainly six linetypes that can be used and these values are 0=blank, 1=solid (default), 2=dashed, 3=dotted, 4=dotdash, 5=longdash, 6=twodash.
Change manually the appearance of lines scale_linetype_manual() : to change line types. scale_color_manual() : to change line colors. scale_size_manual() : to change the size of lines.
The type of line you can be specified based on a number or a string. In R the default line type is “solid”. In the case of ggplot2 package, the parameters linetype and size are used to decide the type and the size of lines, respectively.
The trick is to map both colour
and linetype
to State
, and then to define scale_linetype_manual
with 16 levels:
ggplot(mort3, aes(x = year, y = BCmort, col = State, linetype = State)) + geom_line(lwd = 1) + scale_linetype_manual(values = c(rep("solid", 10), rep("dashed", 6))) + scale_color_manual(values = c(brewer.pal(10, "Set3"), brewer.pal(6, "Set3"))) + opts(title = "BC mortality") + theme_bw()
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