time    POINT_Y POINT_X
00:00   106.78  207.44
00:30   106.61  207.6
01:00   103.72  208.33
01:30   102.57  207.35
02:00   102.27  206.3
02:30   101.6   206.43
03:00   100.66  206.73
03:30   101.11  206.5
04:00   100.95  206.63
04:30   102.02  206.27
05:00   105.83  207.93
05:30   106.98  207.15
06:00   107.32  206.28
06:30   108.36  204.7
07:00   107.97  203.41
07:30   107.76  202.63
08:00   107.85  201.13
08:30   107.6   198.74

Lines <- "time    POINT_Y POINT_X
00:00   106.78  207.44
00:30   106.61  207.6
01:00   103.72  208.33
01:30   102.57  207.35
02:00   102.27  206.3
02:30   101.6   206.43
03:00   100.66  206.73
03:30   101.11  206.5
04:00   100.95  206.63
04:30   102.02  206.27
05:00   105.83  207.93
05:30   106.98  207.15
06:00   107.32  206.28
06:30   108.36  204.7
07:00   107.97  203.41
07:30   107.76  202.63
08:00   107.85  201.13
08:30   107.6   198.74
"

library(zoo)
library(chron)
to.times <- function(x) times(paste0(x, ":00"))

# z <- read.zoo("myfile", header = TRUE, FUN = to.times)
z <- read.zoo(text = Lines, header = TRUE, FUN = to.times)

plot(z)