R - plot temperature profile over time

Question

I have the following data frame containing water temperature measurements for multiple depths and dates:

wtemp <- structure(list(Date = structure(c(12604, 12604, 12604, 12604, 
12604, 12604, 12604, 12604, 12604, 12604, 12604, 12604, 12604, 
12604, 12604, 12680, 12680, 12680, 12680, 12680, 12680, 12680, 
12680, 12680, 12680, 12680, 12680, 12680, 12680, 12680, 12714, 
12714, 12714, 12714, 12714, 12714, 12714, 12714, 12714, 12714, 
12714, 12714, 12714, 12714, 12714, 12751, 12751, 12751, 12751, 
12751, 12751, 12751, 12751, 12751, 12751, 12751, 12751, 12751, 
12751, 12751, 12770, 12770, 12770, 12770, 12770, 12770, 12770, 
12770, 12770, 12770, 12770, 12770, 12770, 12770, 12770, 12806, 
12806, 12806, 12806, 12806, 12806, 12806, 12806, 12806, 12806, 
12806, 12806, 12806, 12806, 12806, 12848, 12848, 12848, 12848, 
12848, 12848, 12848, 12848, 12848, 12848, 12848, 12848, 12848, 
12848, 12848, 12885, 12885, 12885, 12885, 12885, 12885, 12885, 
12885, 12885, 12885, 12885, 12885, 12885, 12885, 12885, 12918, 
12918, 12918, 12918, 12918, 12918, 12918, 12918, 12918, 12918, 
12918, 12918, 12918, 12918, 12918, 12987, 12987, 12987, 12987, 
12987, 12987, 12987, 12987, 12987, 12987, 12987, 12987, 12987, 
12987, 12987, 13015, 13015, 13015, 13015, 13015, 13015, 13015, 
13015, 13015, 13015, 13015, 13015, 13015, 13015, 13015, 13051, 
13051, 13051, 13051, 13051, 13051, 13051, 13051, 13051, 13051, 
13051, 13051, 13051, 13051, 13051, 13103, 13103, 13103, 13103, 
13103, 13103, 13103, 13103, 13103, 13103, 13103, 13103, 13103, 
13103, 13103), class = "Date"), Depth = structure(c(1L, 7L, 15L, 
16L, 17L, 2L, 3L, 4L, 5L, 6L, 8L, 9L, 10L, 11L, 12L, 1L, 7L, 
15L, 16L, 17L, 2L, 3L, 4L, 5L, 6L, 8L, 9L, 10L, 11L, 12L, 1L, 
7L, 15L, 16L, 17L, 2L, 3L, 4L, 5L, 6L, 8L, 9L, 10L, 11L, 12L, 
1L, 7L, 15L, 16L, 17L, 2L, 3L, 4L, 5L, 6L, 8L, 9L, 10L, 11L, 
12L, 1L, 7L, 15L, 16L, 17L, 2L, 3L, 4L, 5L, 6L, 8L, 9L, 10L, 
11L, 12L, 1L, 7L, 15L, 16L, 17L, 2L, 3L, 4L, 5L, 6L, 8L, 9L, 
10L, 11L, 12L, 1L, 7L, 15L, 16L, 17L, 2L, 3L, 4L, 5L, 6L, 8L, 
9L, 10L, 11L, 12L, 1L, 7L, 15L, 16L, 17L, 2L, 3L, 4L, 5L, 6L, 
8L, 9L, 10L, 11L, 12L, 1L, 7L, 15L, 16L, 17L, 2L, 3L, 4L, 5L, 
6L, 8L, 9L, 10L, 11L, 12L, 1L, 7L, 15L, 16L, 17L, 2L, 3L, 4L, 
5L, 6L, 8L, 9L, 10L, 11L, 12L, 1L, 7L, 15L, 16L, 17L, 2L, 3L, 
4L, 5L, 6L, 8L, 9L, 10L, 11L, 12L, 1L, 7L, 15L, 16L, 17L, 2L, 
3L, 4L, 5L, 6L, 8L, 9L, 10L, 11L, 12L, 1L, 7L, 15L, 16L, 17L, 
2L, 3L, 4L, 5L, 6L, 8L, 9L, 10L, 11L, 12L), .Label = c("0", "10", 
"12", "14", "16", "18", "2", "20", "22", "24", "26", "28", "30", 
"32", "4", "6", "8", "AR"), class = "factor"), T_water = c(33L, 
33L, 32L, 32L, 31L, 31L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 
29L, 32L, 32L, 32L, 32L, 31L, 31L, 30L, 30L, 30L, 30L, 30L, 30L, 
30L, 30L, 30L, 33L, 33L, 32L, 32L, 31L, 31L, 30L, 30L, 30L, 30L, 
30L, 30L, 30L, 30L, 30L, 32L, 32L, 32L, 31L, 31L, 31L, 31L, 31L, 
31L, 31L, 31L, 31L, 31L, 30L, 30L, 31L, 31L, 31L, 31L, 31L, 31L, 
31L, 31L, 31L, 31L, 31L, 31L, 31L, 31L, 32L, 30L, 30L, 30L, 30L, 
30L, 30L, 30L, 30L, 30L, 31L, 31L, 31L, 31L, 31L, 31L, 30L, 30L, 
30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 29L, 29L, 28L, 28L, 28L, 
30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 
30L, 30L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 
29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 29L, 
29L, 29L, 28L, 28L, 28L, 28L, 31L, 31L, 31L, 31L, 30L, 30L, 30L, 
30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 32L, 32L, 32L, 32L, 31L, 
31L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 33L, 33L, 32L, 
32L, 31L, 31L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L, 30L)), .Names = c("Date", 
"Depth", "T_water"), row.names = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 
8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 17L, 18L, 19L, 20L, 21L, 
22L, 23L, 24L, 25L, 26L, 27L, 28L, 29L, 30L, 31L, 33L, 34L, 35L, 
36L, 37L, 38L, 39L, 40L, 41L, 42L, 43L, 44L, 45L, 46L, 47L, 49L, 
50L, 51L, 52L, 53L, 54L, 55L, 56L, 57L, 58L, 59L, 60L, 61L, 62L, 
63L, 65L, 66L, 67L, 68L, 69L, 70L, 71L, 72L, 73L, 74L, 75L, 76L, 
77L, 78L, 79L, 81L, 82L, 83L, 84L, 85L, 86L, 87L, 88L, 89L, 90L, 
91L, 92L, 93L, 94L, 95L, 97L, 98L, 99L, 100L, 101L, 102L, 103L, 
104L, 105L, 106L, 107L, 108L, 109L, 110L, 111L, 113L, 114L, 115L, 
116L, 117L, 118L, 119L, 120L, 121L, 122L, 123L, 124L, 125L, 126L, 
127L, 131L, 132L, 133L, 134L, 135L, 136L, 137L, 138L, 139L, 140L, 
141L, 142L, 143L, 144L, 145L, 149L, 150L, 151L, 152L, 153L, 154L, 
155L, 156L, 157L, 158L, 159L, 160L, 161L, 162L, 163L, 167L, 168L, 
169L, 170L, 171L, 172L, 173L, 174L, 175L, 176L, 177L, 178L, 179L, 
180L, 181L, 185L, 186L, 187L, 188L, 189L, 190L, 191L, 192L, 193L, 
194L, 195L, 196L, 197L, 198L, 199L, 203L, 204L, 205L, 206L, 207L, 
208L, 209L, 210L, 211L, 212L, 213L, 214L, 215L, 216L, 217L), class = "data.frame")

On the x-axis I need to show the dates, on the y-axis the temperature, and the multiple lines correspond to the depths. Specifically, I am trying to reproduce this figure:

I am trying to use this command:

library(lattice)
xyplot(T_water ~ Date, data = wtemp, type = "l", auto.key=TRUE)

which works only partially. I need to plot the other lines too. It doesn't need to be using lattice, other libraries (such as ggplot2) can be used too.

How to achieve that?

Thanks

Answer 1

Here is my proposal. I am using the normal plot function and this should work:

# First get a subset of your dataframe of the rows where depth=0
sub <- wtemp[wtemp$Depth==0,]
# Define line colours
colours <- rainbow(14)
# And draw the respective plot
plot(sub$Date,sub$T_water,type="l",col=colours[1], xaxt='n')
# Draw nicer ticks
minDate <- as.Date("2004-07-05")
maxDate <- as.Date("2005-11-16")
axis.Date(1, at=seq(minDate,maxDate ,"month"), format="%m/%d/%Y")
# Loop through all other subsets and create a line which gets added to the plot 
for(i in 2:28){
    sub <- wtemp[wtemp$Depth==i,]
    lines(sub$Date,sub$T_water,col=colours[i/2+1])
}
# Add a legend: http://www.r-bloggers.com/adding-a-legend-to-a-plot/
legend(as.Date("2005-05-05"),33,           # legend position 
seq(0,28,2),            # what to display: values 0 to 28 with an interval of 2 
lty=1,                  # gives the legend appropriate symbols (lines)
lwd=2.5,                # line width
col=colours)            # gives the legend lines the correct colour as defined above

Update: If you only want to display selected values:

# Define values to display
valueDsp <- c(0,12,24)
# First get a subset of your dataframe of the rows where depth=0
sub <- wtemp[wtemp$Depth==valueDsp[1],]
# Define line colours
colours <- rainbow(length(valueDsp))
# And draw the respective plot
plot(sub$Date,sub$T_water,type="l",col=colours[1], xaxt='n')
# Draw nicer ticks
minDate <- as.Date("2004-07-05")
maxDate <- as.Date("2005-11-16")
axis.Date(1, at=seq(minDate,maxDate ,"month"), format="%m/%d/%Y")
# Loop through all other subsets and create a line which gets added to the plot 
for(i in 2:length(valueDsp)){
    sub <- wtemp[wtemp$Depth==valueDsp[i],]
    lines(sub$Date,sub$T_water,col=colours[i])
}
# Add a legend: http://www.r-bloggers.com/adding-a-legend-to-a-plot/
legend(as.Date("2005-05-05"),33,           # legend position 
valueDsp,            # what to display: values 0 to 28 with an interval of 2 
lty=1,                  # gives the legend appropriate symbols (lines)
lwd=2.5,                # line width
col=colours)            # gives the legend lines the correct colour as defined above

You can easily adjust the script to change colours, displayed values, legend and so on.

Ps. Are you aware that following months are missing in the dataset:

2004-08
2005-02
2005-06
2005-10

Kind Regards

Answer 2

Based on the comments, I came out with the following answer:

xyplot(T_water ~ Date, group = Depth, data = wtemp, t='l')

However, the plot had too many lines, and I wanted to keep only depths 0,12 and 24. This is how I've done it:

# Select depths
wtemp <- wtemp[wtemp$Depth %in% c("0","12","24"),]

# Drop old depths
wtemp$Depth <- levels(droplevels(wtemp$Depth))

# Plot new data
xyplot(T_water ~ Date, group = Depth, data = wtemp, t='b',auto.key =list(points = FALSE, columns=3, lines = TRUE))

Thanks to those who helped.