用ggplot2繪製粗體字母？

Question

我使用ggplot2構建了一個包含四個繪圖的圖形，每個繪圖都由一個特定的建模域組成。我想用黑體上的字母進行以下繪圖。使用符號太麻煩了，因爲我有8個類別，符號看起來太相似。

下面是一個可再現的例子。

數據：

Covariate.Weights.Data= structure(list(Species = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 
2L, 2L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 6L, 6L, 
6L, 6L, 7L, 7L, 7L, 7L, 8L, 8L, 8L, 8L, 1L, 1L, 1L, 1L, 2L, 2L, 
2L, 2L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 6L, 6L, 
6L, 6L, 7L, 7L, 7L, 7L, 8L, 8L, 8L, 8L, 1L, 1L, 1L, 1L, 2L, 2L, 
2L, 2L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 6L, 6L, 
6L, 6L, 7L, 7L, 7L, 7L, 8L, 8L, 8L, 8L), .Label = c("American black duck", 
"American wigeon", "Blue-winged teal", "Gadwall", "Green-winged teal", 
"Mallard", "Northern pintail", "Northern shoveler"), class = "factor"), 
    Flyway = structure(c(1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 
    2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
    1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 
    2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
    1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 
    2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
    1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L), .Label = c("Atlantic", 
    "Mississippi"), class = "factor"), Season = structure(c(1L, 
    1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 
    1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 
    2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 
    2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 
    1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 
    1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 2L, 1L, 1L, 2L, 
    2L, 1L, 1L, 2L, 2L), .Label = c("Fall", "Spring"), class = "factor"), 
    Covariates = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 
    2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
    2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 
    3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
    3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L), .Label = c("Forage", 
    "Habitat", "Survey"), class = "factor"), Weights = c(0.31, 
    1, 0, 0.96, 0, 0, 1, 0, 1, 1, 0, 0.06, 1, 1, 1, 0.06, 0, 
    1, 0.01, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0.82, 1, 1, 0.31, 
    0.43, 0, 0.82, 1, 1, 1, 0.92, 1, 0, 1, 0.97, 1, 1, 0, 0.94, 
    1, 1, 0.05, 0, 1, 1, 1, 1, 1, 1, 1, 0.07, 0.99, 1, 1, 1, 
    0.69, 0, 1, 0.04, 0, 0, 0, 0.08, 0, 0, 0, 0.02, 0, 0, 0, 
    0, 0, 0, 0.94, 0, 0, 0, 0, 0, 0, 0, 0, 0.93, 0.01, 0, 0, 
    0)), .Names = c("Species", "Flyway", "Season", "Covariates", 
"Weights"), class = "data.frame", row.names = c(NA, -96L)) 

簡介：

require(ggplot2)  
Covariates.Weights.Plot = 
     ggplot(Covariate.Weights.Data, aes(x=Covariates,y=Weights,shape=Species)) + 
     facet_grid(Flyway~Season) + ylab("Relative Importance") + 
     geom_point(size=5, position=position_jitter(h=0.1,w=0.3)) + 
     scale_shape_manual(values=LETTERS[c(1,23,2,7,20,13,16,19)]) + 
     theme(text=element_text(size=20, face="bold"), 
      axis.text.y=element_text(size=20), 
      axis.text.x=element_text(size=20), 
      axis.title.y=element_text(size=30, face="bold", vjust=1), 
      axis.title.x=element_text(size=30, face="bold", vjust=0), 
      strip.text=element_text(size=30, colour="black", face="bold", 
            vjust=1)) 
    Covariates.Weights.Plot 

Answer 1

也許ggplot專家就會知道，如果這是可能直接在ggplot，但由於ggplot使用grid可以

require(grid) 
grid.edit("geom_point.points", grep = TRUE, global=TRUE, gp = gpar(fontface="bold")) 

以後大膽的字母事實。

Answer 2

您可以在頂部繪製稍大的字母。爲了讓他們正確對齊（至少很容易），最好使用閃避。

ggplot(...)+...+ 
    geom_point(size=5, position=position_dodge(width=.6)) + 
    geom_point(size=5.8,position=position_dodge(width=.6))+ 
    ...