使用geom_text在geom_point上组织文本

Question

我有一个线图，其中一些时间点很难通过单独的颜色来区分，因此我想在图上标记时间点，但是标签重叠（见下图）难以阅读标签。

情节目前看起来像这样，

我想知道是否有办法'堆叠'标签或某种方式（脚本）可以确保它们不重叠。像这样的东西，

任何帮助都将不胜感激。

这是我用来制作情节的代码，

 require(ggplot2)
 require(plyr)
 require(reshape)

# create sample data
set.seed(666)
dfn <- data.frame(
Referral  = seq(as.Date("2007-01-15"), len= 26, by="23 day"),
VISIT01  = seq(as.Date("2008-06-15"), len= 24, by="15 day")[sample(30, 26)],
VISIT02  = seq(as.Date("2008-12-15"), len= 24, by="15 day")[sample(30, 26)],
VISIT03  = seq(as.Date("2009-01-01"), len= 24, by="15 day")[sample(30, 26)],
VISIT04  = seq(as.Date("2009-03-30"), len= 24, by="60 day")[sample(30, 26)],
VISIT05  = seq(as.Date("2010-11-30"), len= 24, by="6 day")[sample(30, 26)],
VISIT06  = seq(as.Date("2011-01-30"), len= 24, by="6 day")[sample(30, 26)],
Discharge = seq(as.Date("2012-03-30"), len= 24, by="30 day")[sample(30, 26)],
Patient  = factor(1:26, labels = LETTERS),
openCase  = rep(0:1, 100)[sample(100, 26)])

 # set today's data for cases that do not have an Discharge date
 dfn$Discharge[ is.na(dfn$Discharge) ] <- as.Date("2014-01-30")

 mdfn <- melt(dfn, id=c('Patient', 'openCase'), variable_name = "Visit")
 names(mdfn)[4] <- 'Year' # rename 

 # order data in mdfn by 'Referral' in dfn
 mdfn$Patient <- factor(mdfn$Patient,levels = 
 (dfn$Patient[order(dfn$Referral)]),ordered = TRUE)

 # subset a dataset to avoid 'Discharge' for cases that are not closed 
 mdfn2 <- subset(mdfn,!(Visit=="Discharge" & Year > as.Date("2014-01-01")))

 # the plot as it looks now
 ggplot(mdfn, aes(Year, Patient)) +
     geom_blank() +
     geom_line(data = mdfn[mdfn$openCase == 0,], colour = "black") +
     geom_line(data = mdfn[mdfn$openCase == 1,], colour = "grey") +
     geom_point(data = mdfn2, aes(colour = Visit), size = 4, shape = 124) + 
     geom_text(data=mdfn2, mapping=aes(x=Year, y=Patient, 
     label=substr(Visit, 1, 7), colour=Visit), size=2, 
     vjust=-.4, hjust=-.1, angle = 00) 

Answer 1

您可以根据访问的数值更改标签的垂直位置。

关键是：

 y=(as.numeric(Patient)+0.25*as.numeric(Visit)%%3)-0.12

目前产生：
根据访问（%% 3）的值，可以增加或减少3个不同的级别 每个级别由y个标签（0.25）之间的距离分开四分之一 第一个标签是水平线以下0.12 第二个是0.12以上

require(ggplot2)
require(plyr)
require(reshape)
# create sample data
set.seed(666)
dfn <- data.frame(
  Referral  = seq(as.Date("2007-01-15"), len= 26, by="23 day"),
  VISIT01  = seq(as.Date("2008-06-15"), len= 24, by="15 day")[sample(30, 26)],
  VISIT02  = seq(as.Date("2008-12-15"), len= 24, by="15 day")[sample(30, 26)],
  VISIT03  = seq(as.Date("2009-01-01"), len= 24, by="15 day")[sample(30, 26)],
  VISIT04  = seq(as.Date("2009-03-30"), len= 24, by="60 day")[sample(30, 26)],
  VISIT05  = seq(as.Date("2010-11-30"), len= 24, by="6 day")[sample(30, 26)],
  VISIT06  = seq(as.Date("2011-01-30"), len= 24, by="6 day")[sample(30, 26)],
  Discharge = seq(as.Date("2012-03-30"), len= 24, by="30 day")[sample(30, 26)],
  Patient  = factor(1:26, labels = LETTERS),
  openCase  = rep(0:1, 100)[sample(100, 26)])

# set today's data for cases that do not have an Discharge date
dfn$Discharge[ is.na(dfn$Discharge) ] <- as.Date("2014-01-30")

mdfn <- melt(dfn, id=c('Patient', 'openCase'), variable_name = "Visit")
names(mdfn)[4] <- 'Year' # rename 

# order data in mdfn by 'Referral' in dfn
mdfn$Patient <- factor(mdfn$Patient,levels = 
  (dfn$Patient[order(dfn$Referral)]),ordered = TRUE)

# subset a dataset to avoid 'Discharge' for cases that are not closed 
mdfn2 <- subset(mdfn,!(Visit=="Discharge" & Year > as.Date("2014-01-01")))

# the plot as it looks now
ggplot(mdfn, aes(Year, Patient)) +
  geom_blank() +
  geom_line(data = mdfn[mdfn$openCase == 0,], colour = "black") +
  geom_line(data = mdfn[mdfn$openCase == 1,], colour = "grey") +
  geom_point(data = mdfn2, aes(colour = Visit), size = 4, shape = 124) + 
  geom_text(data=mdfn2, mapping=aes(x=Year, y=(as.numeric(Patient)+0.25*as.numeric(Visit)%%3)-0.12, 
                                    label=substr(Visit, 1, 7), colour=Visit), size=2, 
            hjust=-.1, angle = 00)