Question

我有一个简单的XY图，显示了以小时和分钟为单位的（Y）潮位和（X）时间戳。

我想在此图上叠加一组在特定时间位置获取的数据的箱形图（它们是从n = 15个条目的栅格堆栈中生成的）。因此，我尝试按时间戳匹配箱形图的位置。

虽然在X轴上的匹配有效，但箱形图未正确显示，它们被埋在第一个图中（在第一个图中更改ylim时可见）。

有人能建议一种有效的方法来处理R基吗？只需在正确的时间让箱型图覆盖潮汐？

这是我使用的代码：

# example for experiment 1
# aim: to match the X axis (time) boxplot position with that of the tide plot based on a POSIXct timestamp

#Tide level and timestamp file
ST1502tidelevel <- read.table("/st1502_LAT - Copy.tide", h = T, colClasses = "character")

#ratser stack from which the boxplots are derived 
library(raster)
setwd("/Stacks_boxplots")
KWGSbox  <- stack("KWGSboxplots.tif")

#the correct timestamp of each boxplot 
Timestamp = c("201502031648",
              "201502031746",
              "201502031838",
              "201502031947", 
              "201502032042",
              "201502032138", 
              "201502032234", 
              "201502032341", 
              "201502040043", 
              "201502040141",
              "201502040233", 
              "201502040333", 
              "201502040427", 
              "201502040521",
              "201502040623")

#make it as time
Timestamp <- strptime(Timestamp, format = "%Y%m%d%H%M")
# p <-as.POSIXct(p, "%Y%m%d%H%M", tz ="Europe/Paris")
# df[["Timestamp"]] <- p

#convert the timestamp in the tide file to match the timestamp of the boxplots at argument
ST1502tidelevel$timestamp <- as.POSIXct(ST1502tidelevel$timestamp, "%Y%m%d%H%M", tz ="Europe/Paris")

#make a range for the tide plot - by hour
range(as.POSIXct(paste0( unique(Timestamp), " ")))
x.range <- as.POSIXct(c("2015-02-03 16:30:00 CET", "2015-02-04 06:30:00 CET")) 

#positions of boxplots
x.hour <- as.POSIXct(paste0( unique(Timestamp), " "))

#plot of tide with time axis by hour
par(mar=c(4, 4.2, 2.5, 4.2))                           
plot(ST1502tidelevel, 
     xlab = "Time", 
     xaxt = "n", 
     ylab = "Tide Level", 
     type = "l",
     lwd = 2,
     ylim = c(0, 5), 
     xlim = x.range)     

axis.POSIXct(1, at = seq(x.range[1], x.range[2], by = "hour"), labels = TRUE, las = 1, cex = 0.1)


#add boxplot time series at correct X positions
boxplot(KWGSbox,
        outline=FALSE,
        col = "lightgrey",
        at = x.hour, 
        add = T)

通过基准R中的时间戳来匹配基础图的X轴上的箱线图位置

0 个答案: