这段代码创建了一个很好的绘图,但我想在y=50处添加一条水平黑线,让图例显示一条黑线,并在图例中显示文本"截止",但在图例中为源留下点.我可以用geom_线添加线,但无法在图例中获得线.
library(ggplot2)
the.data <- read.table( header=TRUE, sep=",",
text="source,year,value
S1,1976,56.98
S1,1977,55.26
S1,1978,68.83
S1,1979,59.70
S1,1980,57.58
S1,1981,61.54
S1,1982,48.65
S1,1983,53.45
S1,1984,45.95
S1,1985,51.95
S1,1986,51.85
S1,1987,54.55
S1,1988,51.61
S1,1989,52.24
S1,1990,49.28
S1,1991,57.33
S1,1992,51.28
S1,1993,55.07
S1,1994,50.88
S2,1993,54.90
S2,1994,51.20
S2,1995,52.10
S2,1996,51.40
S3,2002,57.95
S3,2003,47.95
S3,2004,48.15
S3,2005,37.80
S3,2006,56.96
S3,2007,48.91
S3,2008,44.00
S3,2009,45.35
S3,2010,49.40
S3,2011,51.19")
ggplot(the.data, aes( x = year, y = value ) ) +
geom_point(aes(colour = source)) +
geom_smooth(aes(group = 1))