增加图例项中GGPLOT2

Question

我有THID数据帧：

头（X）

 Date Company Region Units 
1 1/1/2012 Gateway America  0 
2 1/1/2012 Gateway Europe  0 
3 1/1/2012 Gateway America  0 
4 1/1/2012 Gateway Americas  0 
5 1/1/2012 Gateway Europe  0 
6 1/1/2012 Gateway Pacific  0 

X dput（X）

structure(list(Date = 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, 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), .Label = c("1/1/2012", 
"1/12/2012", "1/2/2012"), class = "factor"), Company = structure(c(1L, 
1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L), .Label = c("Gateway", "HP", "IBM"), class = "factor"), 
    Region = structure(c(1L, 3L, 1L, 2L, 3L, 4L, 2L, 1L, 3L, 
    1L, 2L, 3L, 4L, 2L, 1L, 3L, 1L, 2L, 3L, 4L, 2L, 1L, 3L, 1L, 
    2L, 3L, 4L, 2L, 1L, 3L, 1L, 2L, 3L, 4L, 2L, 1L, 3L, 1L, 2L, 
    3L, 4L, 2L, 1L, 3L, 1L, 2L, 3L, 4L, 2L, 1L, 3L, 1L, 2L, 3L, 
    4L, 2L, 1L, 3L, 1L, 2L, 3L, 4L, 2L, 1L, 3L, 1L, 2L, 3L, 4L, 
    2L, 1L, 3L, 1L, 2L, 3L, 4L, 2L, 1L, 3L, 1L, 2L, 3L, 4L, 2L 
    ), .Label = c("America", "Americas", "Europe", "Pacific"), class = "factor"), 
    Units = c(1L, 3L, 1L, 6L, 20L, 2L, 2L, 10L, 2L, 1L, 2L, 4L, 
    6L, 30L, 2L, 15L, 10L, 3L, 4L, 7L, 9L, 12L, 34L, 50L, 3L, 
    2L, 4L, 3L, 1L, 3L, 3L, 1L, 4L, 0L, 1L, 0L, 0L, 1L, 0L, 4L, 
    0L, 0L, 0L, 0L, 5L, 0L, 8L, 0L, 0L, 0L, 0L, 0L, 9L, 0L, 56L, 
    10L, 0L, 0L, 5L, 7L, 0L, 0L, 8L, 0L, 2L, 0L, 4L, 0L, 5L, 
    7L, 0L, 0L, 8L, 10L, 0L, 6L, 0L, 4L, 4L, 0L, 2L, 0L, 5L, 
    0L)), .Names = c("Date", "Company", "Region", "Units"), class = "data.frame", row.names = c(NA, 
-84L)) 

我想建立一个热地图：

ggplot(x, aes(Date, Company, fill=Units)) + geom_tile(aes(fill=Units)) + facet_grid(~Region) + scale_fill_gradient(low="white", high="red") 

这个命令的作品，但我需要能够使用不同的颜色，而不是白色和红色，并增加了传说上的剥落。现在，默认情况下，有5个传说。我喜欢增加10.O将是白色的，其他应该与白色明显不同，以便用户能够注意到它。

我该如何使用ggplot增加图例值的数量并为每个图例分配不同的颜色？

Answer 1

我发现它非常丰富的使用quantiles来绘制heatmapsas done here in this blog。这有助于生成倾斜的颜色集（如博客所示）。假设数据与您的数据相似（相当高的0），然后通过计算适当的分位数，我们可以创建一个倾斜的色彩图，该色彩图具有合适的标签，在视觉上非常出色且信息丰富。我修改了已经为此问题链接的博客地图中的代码，并添加了更多解释。博客文章必须获得所有的想法和实施的功劳。

在进入代码之前，我们必须对您的数据使用quantiles进行一些分析，以查看要使用的分位数。通过这样做：

quantile(x$Units, seq(0, 1, length.out = 25) 

#  0% 4.166667% 8.333333%  12.5% 16.66667% 20.83333%  25% 29.16667% 33.33333% 
# 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 
# 37.5% 41.66667% 45.83333%  50% 54.16667% 58.33333%  62.5% 66.66667% 70.83333% 
# 1.00000 1.00000 2.00000 2.00000 3.00000 3.00000 4.00000 4.00000 5.00000 
#  75% 79.16667% 83.33333%  87.5% 91.66667% 95.83333%  100% 
# 6.00000 7.00000 8.00000 9.62500 10.16667 25.41667 56.00000 

你看到0%位数对应于数据Units=0。并且直到33%（准确地说是33.33%）。所以，也许我们选择38%作为下一个分位数。然后说，60%,75%,90%并最终以100%完成。现在，我们有足够的水平，你想要的水平，他们在你的数据有意义的水平。

我们将需要zoo包来完成此操作。现在让我们来构建数据：

require(zoo) # for rollapply 
# the quantiles we just decided to categorise the data into classes. 
qtiles <- quantile(x$Units, probs = c(0, 38, 60, 75, 90, 100)/100) 
# a color palette 
c_pal  <- colorRampPalette(c("#3794bf", "#FFFFFF", 
         "#df8640"))(length(qtiles)-1) 
# since we are using quantile classes for fill levels, 
# we'll have to generate the appropriate labels 
labels <- rollapply(round(qtiles, 2), width = 2, by = 1, 
         FUN = function(i) paste(i, collapse = " : ")) 
# added the quantile interval in which the data falls, 
# which will be used for fill 
x$q.units <- findInterval(x$Units, qtiles, all.inside = TRUE) 

# Now plot 
library(ggplot2) 
p <- ggplot(data = x, aes(x = Date, y = Company, fill = factor(q.units))) 
p <- p + geom_tile(color = "black") 
p <- p + scale_fill_manual(values = c_pal, name = "", labels = labels) 
p <- p + facet_grid(~ Region) 
p <- p + theme(axis.text.x = element_text(angle = 90, hjust = 1)) 
p 

你得到这样的：

希望这有助于。

编辑：您还可以访问colorbrewer2.org以获得不错的调色板和自己设置颜色。例如：

# try out these colors: 
c_pal  <- c("#EDF8FB", "#B3CDE3", "#8C96C6", "#8856A7", "#810F7C") 
c_pal  <- c("#FFFFB2", "#FECC5C", "#FD8D3C", "#F03B20", "#BD0026") 

另外，尝试在代码中设置geom_tile(color = "black", alpha = 0.5")alpha。