Temperature curve in R

Question

I'd like to create two temperature curves in one plot. My Dataframe looks like this:

temp <- read.table(text = "     Time        Temp1       Temp2
                           1  00:00     18.62800    18.54458
                           2   00:10     18.60025    18.48283
                           3   00:20     18.57250    18.36767
                           4   00:30     18.54667    18.36950
                           5   00:40     18.51483    18.36550
                           6   00:50     18.48325    18.34783
                           7   01:00     18.45733    18.22625
                           8   01:10     18.43767    18.19067
                           9   01:20     18.41583    18.22042
                           10  01:30     18.39608    18.21225
                           11  01:40     18.37625    18.18658
                           12  01:50     18.35633    18.05942
                           13  02:00     18.33258    18.04142", header = T)

How can I get clean curves (no edges on the lines like a linechart) by only showing each hour (24 hours) on the x-axis? Im thinking about something with ggplot2 but I'm still learning R basics.

Answer 1

If you want to plot all values but only have full hours as x-axis labels you can plot the data with the ggplot package and use the scale_x_discrete() option to specify the breaks.

library(ggplot2)

is_full_time <- grepl(':00', temp$Time)
ggplot(temp, aes(x = Time, y = Temp1, group = 1)) + geom_line() + scale_x_discrete(breaks = temp$Time[is_full_time])

http://ggplot2.tidyverse.org/reference/scale_discrete.html

Answer 2

We can use the tidyverse for this. First we "clean" the data from all unnecessary rows by only taking time values with 00 minutes and then we use a ggplot to visualize the temperatures.

library(tidyverse)

cleanTemp <- temp %>% filter(grepl(pattern = ":00", Time))

ggplot(cleanTemp, aes(x = Time, y = Temp1, group = 1)) + 
  geom_line()

Temp2 can be added to the plot with

geom_line(aes(y = Temp2), color = "red")

you can also use lubridate to subset the Time column:

temp$Time <- hm(temp$Time)
cleanTemp <- temp[minute(temp$Time) == 0,]