两行嵌套x变量的轴标签（年份低于几个月） [英] Axis labels on two lines with nested x variables (year below months)
问题描述
我想在横轴上显示月份（缩写形式），相应的年份会打印一次。我知道如何显示月份年份：
一年中不必要的重复使标签混乱。相反，我想这样的事情：
除那年会在低于的月份打印。
我在轴标上方打印年，因为这是我能做的最好的。这遵循 annotate（）函数的限制，如果它位于绘图区域之外，该函数将被剪切。我知道基于 annotate_custom（）的可能解决方法，但我无法让它们处理日期对象（我没有尝试将日期转换为数字并返回到再次约会，因为它似乎比希望的更复杂）
我想知道新的 dup_axis（）可能因此被劫持。如果不是将复制的轴发送到面板的另一侧，而是将它发送到复制轴下方几行，那么也许只需要用 panel.grid设置一个轴即可.major 空白并且标签设置为％b ，而另一个轴将具有 panel.grid.minor 空白并将标签设置为％Y 。 （另外一个挑战是年份标签会被转移到10月份，而不是1月份）。
这些问题是相关的。然而，就我而言， annotate_custom（）函数和 textGrob（）函数在日期中表现不佳告诉。
请注意，采用这种方法，如果有在一年的开始或结束时缺少日期（通过缺失，我的意思是这些日期的行甚至没有出现在数据中），那么x轴将开始/结束在数据的第一个/最后一个日期那一年，而不是从1月1日到12月31日。在这种情况下，您需要为缺失日期添加行，并为值添加 NA ，或者插入值。此外，使用这种方法，在一年的12月31日和下一年的1月1日之间没有空间或线路，因此每年都会出现间断。
选项1b：分面+居中的月份标签
解决@ AF7的评论。您可以通过在每个标签前添加一些空格来对月份标签进行居中。但是，您必须手动选择空格数，具体取决于打印到设备时的实际大小。 （可能有一种方法可以基于内部grob测量以编程方式将标签居中，但我不知道如何去做。）我也删除了较小的垂直网格线，并减少了几年之间的线。
ggplot（df，aes（Date，value））+
geom_line（）+
scale_x_date（date_labels = paste（c （rep（，11），％b），collapse =），
date_breaks =month，expand = c（0,0））+
facet_grid日期），space =free_x，scales =free_x，switch =x）+
theme_bw（）+
主题（strip.placement =outside，
strip。 background = element_blank（），
panel.grid.minor.x = element_blank（），
panel.border = element_rect（color =grey70），
panel.spacing = unit（0 ，cm））
选项2a：编辑th e x轴标签grob
下面是一个更复杂和挑剔的方法（尽管它可能会让那些理解网格图形的结构和单位间距比我更好的人自动化）
library（grid）
＃假的数据，额外增加了一年的插图
set.seed（2）
df = data.frame（Date = seq（as.Date（1718-03-01），as.Date 1721-09-20），by =1 day））
df $ value = cumsum（rnorm（nrow（df）））
＃与
p = ggplot（df，aes（Date，value））+
geom_vline（xintercept = as.numeric（df $ Date [yday（df $ Date）== 1]），color =grey60 ）+
geom_line（）+
scale_x_date（date_labels =％b，date_breaks =month，expand = c（0,0））+
theme_bw（）+
主题（panel.grid.minor.x = element_blank（））+
实验室（x =）
现在我们要在下面添加年份值，在每年六月至七月之间。下面的代码通过修改x轴标签grob来做到这一点，并通过@SandyMuspratt从
选项2b：编辑x轴标签grob并居中月份标签
以下是唯一需要更改的变化对选项2a做出了将月份标签放在中间位置的做法，但是，空间数量再次需要手动调整。
＃编辑
＃在蜱之间标记月份标签
ticksB $ children [[1]] $ label = paste0（paste（rep（，7），collapse =），ticksB $ children [[1]] $ label）
＃在x轴标签和年份标签中查找Jun的每个索引
junes = grep（Jun，ticksB $ children [[1 ]] $标签）
ticksB $ children [[1]] $ label [junes] = paste0（ticksB $ children [[1]] $ label [junes]，\\\
，unique（year（df $ Date）））
I would like to display months (in abbreviated form) along the horizontal axis, with the corresponding year printed once. I know how to display month-year:
The un-needed repetition of the year clutters the labels. Instead I would like something like this:
except that the year would be printed below the months.
I printed the year above the axis labels, because that's the best I could do. This follows a limitation of the annotate() function, which gets clipped if it lies outside of the plot area. I am aware of possible workarounds based on annotate_custom(), but I couldn't make them to work with date objects (I did not try to convert dates to numbers and back to dates again, as it seemed more complicated than hopefully necessary)
I'm wondering if the new dup_axis() could be hijacked for this purpose. If instead of sending the duplicated axis to the opposite side of the panel, it could send it a few lines below the duplicated axis, then perhaps it would just be a matter of setting up one axis with panel.grid.major blanked out and the labels set to %b, while the other axis would have panel.grid.minor blanked out and the labels set to %Y. (an added challenge is that the year labels would be shifted to October instead of January)
These questions are related. However, the annotate_custom() function and textGrob() functions do not play well with dates, as far as I can tell.
how-can-i-add-annotations-below-the-x-axis-in-ggplot2
displaying-text-below-the-plot-generated-by-ggplot2
Data and basic code below:
library("ggplot2")
library("scales")
ggplot(data = df, aes(x = Date, y = value)) + geom_line() +
scale_x_date(date_breaks = "2 month", date_minor_breaks = "1 month", labels = date_format("%b %Y")) +
xlab(NULL)
ggplot(data = df, aes(x = Date, y = value)) + geom_line() +
scale_x_date(date_minor_breaks = "2 month", labels = date_format("%b")) +
annotate(geom = "text", x = as.Date("1719-10-01"), y = 0, label = "1719") +
annotate(geom = "text", x = as.Date("1720-10-01"), y = 0, label = "1720") +
xlab(NULL)
# data
df <- structure(list(Date = structure(c(-91455, -91454, -91453, -91452,
-91451, -91450, -91448, -91447, -91446, -91445, -91444, -91443,
-91441, -91440, -91439, -91438, -91437, -91436, -91434, -91433,
-91431, -91430, -91429, -91427, -91426, -91425, -91424, -91423,
-91422, -91420, -91419, -91418, -91417, -91416, -91415, -91413,
-91412, -91411, -91410, -91409, -91408, -91406, -91405, -91404,
-91403, -91402, -91401, -91399, -91398, -91397, -91396, -91395,
-91394, -91392, -91391, -91390, -91389, -91388, -91387, -91385,
-91384, -91382, -91381, -91380, -91379, -91377, -91376, -91375,
-91374, -91373, -91372, -91371, -91370, -91369, -91368, -91367,
-91366, -91364, -91363, -91362, -91361, -91360, -91359, -91357,
-91356, -91355, -91354, -91353, -91352, -91350, -91349, -91348,
-91347, -91346, -91345, -91343, -91342, -91341, -91340, -91339,
-91338, -91336, -91335, -91334, -91333, -91332, -91331, -91329,
-91328, -91327, -91326, -91325, -91324, -91322, -91321, -91320,
-91319, -91315, -91314, -91313, -91312, -91311, -91310, -91308,
-91307, -91306, -91305, -91304, -91303, -91301, -91300, -91299,
-91298, -91297, -91296, -91294, -91293, -91292, -91291, -91290,
-91289, -91287, -91286, -91285, -91284, -91283, -91282, -91280,
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-91270, -91269, -91268, -91266, -91265, -91264, -91263, -91262,
-91261, -91259, -91258, -91257, -91256, -91255, -91254, -91252,
-91251, -91250, -91249, -91248, -91247, -91245, -91244, -91243,
-91242, -91241, -91240, -91238, -91237, -91236, -91235, -91234,
-91233, -91231, -91230, -91229, -91228, -91227, -91226, -91224,
-91223, -91222, -91221, -91220, -91219, -91217, -91216, -91215,
-91214, -91213, -91212, -91210, -91209, -91208, -91207, -91205,
-91201, -91200, -91199, -91198, -91196, -91195, -91194, -91193,
-91192, -91191, -91189, -91188, -91187, -91186, -91185, -91184,
-91182, -91181, -91180, -91179, -91178, -91177, -91175, -91174,
-91173, -91172, -91171, -91170, -91168, -91167, -91166, -91165,
-91164, -91163, -91161, -91160, -91159, -91158, -91157, -91156,
-91154, -91153, -91152, -91151, -91150, -91149, -91147, -91146,
-91145, -91144, -91143, -91142, -91140, -91139, -91138, -91131,
-91130, -91129, -91128, -91126, -91125, -91124, -91123, -91122,
-91121, -91119, -91118, -91117, -91116, -91115, -91114, -91112,
-91111, -91110, -91109, -91108, -91107, -91104, -91103, -91102,
-91101, -91100, -91099, -91097, -91096, -91095, -91094, -91093,
-91091, -91090, -91089, -91088, -91087, -91086, -91084, -91083,
-91082, -91081, -91080, -91079, -91077, -91076, -91075, -91074,
-91073, -91072, -91070, -91069, -91068, -91065, -91063, -91062,
-91061, -91060, -91059, -91058, -91056, -91055, -91054, -91053,
-91052, -91051, -91049, -91048, -91047, -91046, -91045, -91044,
-91042, -91041, -91040, -91039, -91038, -91037, -91035, -91034,
-91033, -91032, -91031, -91030, -91028, -91027, -91026, -91025,
-91024, -91023, -91021, -91020, -91019, -91018, -91017, -91016,
-91014, -91013, -91012, -91011, -91010, -91009, -91007, -91006,
-91005, -91004, -91003, -91002, -91000, -90999, -90998, -90997,
-90996, -90995, -90993, -90992, -90991, -90990, -90989, -90988,
-90986, -90985, -90984, -90983, -90982), class = "Date"), value = c(113,
113, 113, 113, 114, 114, 114, 115, 115, 115, 116, 116, 116, 116,
117, 117, 117, 117, 116, 117, 116, 116, 116, 117, 117, 117, 117,
117, 117, 117, 116, 117, 116, 116, 116, 117, 117, 117, 117, 117,
117, 117, 116, 116, 117, 117, 117, 117, 117, 117, 117, 117, 117,
117, 117, 118, 118, 118, 118, 117, 118, 117, 117, 117, 117, 117,
117, 118, 116, 116, 116, 116, 116, 116, 116, 117, 117, 118, 118,
118, 118, 118, 119, 120, 120, 119, 119, 120, 120, 121, 121, 122,
124, 124, 122, 123, 124, 123, 123, 123, 123, 123, 124, 124, 126,
126, 126, 126, 126, 125, 125, 126, 127, 126, 126, 125, 126, 126,
126, 128, 128, 128, 130, 133, 131, 133, 134, 134, 134, 136, 136,
136, 135, 135, 135, 136, 136, 136, 136, 135, 135, 135, 135, 130,
129, 129, 130, 131, 136, 138, 155, 157, 161, 170, 174, 168, 165,
169, 171, 181, 184, 182, 179, 181, 179, 175, 177, 177, 174, 170,
174, 173, 178, 173, 178, 179, 182, 184, 184, 180, 181, 182, 182,
184, 184, 188, 195, 198, 220, 255, 275, 350, 310, 315, 320, 320,
316, 300, 310, 310, 320, 317, 313, 312, 310, 297, 285, 285, 286,
288, 315, 328, 338, 344, 345, 352, 352, 342, 335, 343, 340, 342,
339, 337, 336, 336, 342, 347, 352, 352, 351, 352, 352, 351, 352,
352, 355, 375, 400, 452, 487, 476, 475, 473, 485, 500, 530, 595,
720, 720, 770, 750, 770, 750, 735, 740, 745, 735, 700, 700, 750,
760, 755, 755, 760, 760, 765, 950, 950, 950, 875, 875, 875, 880,
880, 880, 900, 900, 900, 880, 880, 890, 895, 890, 880, 870, 870,
870, 870, 870, 860, 860, 860, 860, 850, 840, 810, 820, 810, 810,
805, 810, 805, 820, 815, 820, 805, 790, 800, 780, 760, 765, 750,
740, 820, 810, 800, 800, 775, 750, 810, 750, 740, 700, 705, 660,
630, 640, 595, 590, 570, 565, 535, 440, 400, 410, 400, 405, 390,
370, 300, 300, 180, 200, 310, 290, 260, 260, 275, 260, 270, 265,
255, 250, 210, 210, 200, 195, 210, 215, 240, 240, 220, 220, 220,
220, 210, 212, 208, 220, 210, 212, 208, 220, 215, 220, 214, 214,
213, 212, 210, 210, 195, 195, 160, 160, 175, 205, 210, 208, 197,
181, 185)), .Names = c("Date", "value"), row.names = c(NA, 393L
), class = "data.frame")
The code below provides two potential options for adding year labels.
Option 1a: Faceting
You could use faceting to mark the years. For example:
library(ggplot2)
library(lubridate)
ggplot(df, aes(Date, value)) +
geom_line() +
scale_x_date(date_labels="%b", date_breaks="month", expand=c(0,0)) +
facet_grid(~ year(Date), space="free_x", scales="free_x", switch="x") +
theme_bw() +
theme(strip.placement = "outside",
strip.background = element_rect(fill=NA,colour="grey50"),
panel.spacing=unit(0,"cm"))
Note that with this approach, if there are missing dates at the beginning or end of a year (by "missing", I mean rows for those dates are not even present in the data) then the x-axis will start/end at the first/last date in the data for that year, rather than go from Jan-1 to Dec-31. In that case, you'd need to add in rows for the missing dates and either NA for value or interpolate value. In addition, with this method there is no space or line between December 31 of one year and January 1 of the next year, so there's a discontinuity across each year.
Option 1b: Faceting + centered month labels
To address @AF7's comment. You can center the month labels by adding some spaces before each label. But you have to choose the number of spaces manually, depending on the physical size of the plot when you print it to a device. (There's probably a way to center the labels programmatically based on the internal grob measurements, but I'm not sure how to do it.) I've also removed the minor vertical gridlines and lightened the line between years.
ggplot(df, aes(Date, value)) +
geom_line() +
scale_x_date(date_labels=paste(c(rep(" ",11), "%b"), collapse=""),
date_breaks="month", expand=c(0,0)) +
facet_grid(~ year(Date), space="free_x", scales="free_x", switch="x") +
theme_bw() +
theme(strip.placement = "outside",
strip.background = element_blank(),
panel.grid.minor.x = element_blank(),
panel.border = element_rect(colour="grey70"),
panel.spacing=unit(0,"cm"))
Option 2a: Edit the x-axis label grob
Here's a more complex and finicky method (though it could likely be automated by someone who understands the structure and unit spacings of grid graphics better than I do) that avoids the pitfalls of the faceting method described above:
library(grid)
# Fake data with an extra year added for illustration
set.seed(2)
df = data.frame(Date=seq(as.Date("1718-03-01"),as.Date("1721-09-20"), by="1 day"))
df$value = cumsum(rnorm(nrow(df)))
# The plot we'll start with
p = ggplot(df, aes(Date, value)) +
geom_vline(xintercept=as.numeric(df$Date[yday(df$Date)==1]), colour="grey60") +
geom_line() +
scale_x_date(date_labels="%b", date_breaks="month", expand=c(0,0)) +
theme_bw() +
theme(panel.grid.minor.x = element_blank()) +
labs(x="")
Now we want to add the year values below and in between June and July of each year. The code below does that by modifying the x-axis label grob and is adapted from this SO answer by @SandyMuspratt.
# Get the grob
g <- ggplotGrob(p)
# Get the y axis
index <- which(g$layout$name == "axis-b") # Which grob
xaxis <- g$grobs[[index]]
# Get the ticks (labels and marks)
ticks <- xaxis$children[[2]]
# Get the labels
ticksB <- ticks$grobs[[2]]
# Edit x-axis label grob
# Find every index of Jun in the x-axis labels and add a newline and
# then a year label
junes = which(ticksB$children[[1]]$label == "Jun")
ticksB$children[[1]]$label[junes] = paste0(ticksB$children[[1]]$label[junes],
"\n ", unique(year(df$Date)))
# Put the edited labels back into the plot
ticks$grobs[[2]] <- ticksB
xaxis$children[[2]] <- ticks
g$grobs[[index]] <- xaxis
# Draw the plot
grid.newpage()
grid.draw(g)
Option 2b: Edit the x-axis label grob and center the month labels
Below is the only change that needs to be made to Option 2a to center the month labels, but, once again, the number of spaces needs to be tweaked manually.
# Make the edit
# Center the month labels between ticks
ticksB$children[[1]]$label = paste0(paste(rep(" ",7),collapse=""), ticksB$children[[1]]$label)
# Find every index of Jun in the x-axis labels and a year label
junes = grep("Jun", ticksB$children[[1]]$label)
ticksB$children[[1]]$label[junes] = paste0(ticksB$children[[1]]$label[junes], "\n ", unique(year(df$Date)))
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