[R] Lines in a line graph not visible when values are identical
CALUM POLWART
po|c1410 @end|ng |rom gm@||@com
Sat Oct 10 10:44:07 CEST 2026
I'm not entirely sure I've understood the issue, but is this exactly what
jitter exists for
geom_line(position=position_jitter(w=0.1) ...
Adding some slight "bounce" to the plotted likes to make them not overlap.
Jitter always worries me slightly that you are lying slightly with the data
although the idea is it is supposed to be by a neglible amount.
Or, using a dotted line over a solid line can fix this ?
In essence if you have
---------
Currently with both lines under eachother making one of them dotted means
you get
--•---•---•-
The [poor] colour vision world might suggest that's better anyway!
Or I may have misunderstood the problem!
On Thu, 8 Oct 2026, 22:03 Bob Green via R-help, <r-help using r-project.org>
wrote:
> Thanks Rui,
>
> Much appreciated. Regarding why I spelt out
> millimetres, I seldom use them as a measurement
> so it was mostly for that reason and because the
> data was in an Excel spreadsheet.
>
> To get a more direct comparison, I create a panel
> of four bargraphs, one for each parameter by year.
>
> Regards
>
> Bob
>
> At 01:27 AM 10/9/2026, Rui Barradas wrote:
> >Hello,
> >
> >What if instead of colors, you facet the plot by Year?
> >
> >
> >ggplot(DF, aes(x = Parameter, y = Millimetres, group = Year)) +
> > geom_line(linewidth = 1) +
> > geom_point(size = 2) +
> > labs(
> > title = "Parameters by Year",
> > x = "Parameter",
> > y = "Millimetres ($)"
> > ) +
> > facet_wrap(~ Year) +
> > theme_minimal()
> >
> >
> >Also, the data in dput format.
> >
> >DF <-
> >structure(list(Parameter = structure(c(1L, 2L, 3L, 4L, 1L, 2L,
> >3L, 4L, 1L, 2L, 3L, 4L, 1L, 2L, 3L, 4L, 1L, 2L, 3L, 4L, 1L, 2L,
> >3L, 4L, 1L, 2L, 3L, 4L, 1L, 2L, 3L, 4L), levels = c("Tail", "Tail_b",
> >"Nose_b", "Nose"), class = "factor"), Millimetres = c(0, 0, 20.3,
> >74.9, 0, 0, 14, 63.7, 11.2, 2.8, 16.3, 72.6, 0, 0, 17.1, 72.5,
> >11.3, 2.9, 16.9, 74.7, 28.1, 4.9, 6.8, 37.7, 25.9, 5.2, 11.2,
> >68.1, 30.2, 6.35, 15.1, 76.2), Year = c("2010-2012", "2010-2012",
> >"2010-2012", "2010-2012", "2014", "2014", "2014", "2014", "2016",
> >"2016", "2016", "2016", "2023", "2023", "2023", "2023", "2024",
> >"2024", "2024", "2024", "2025C", "2025C", "2025C", "2025C", "2025B",
> >"2025B", "2025B", "2025B", "2026", "2026",
> >"2026", "2026")), row.names = c("1",
> >"2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13",
> >"14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24",
> >"25", "26", "27", "28", "29", "30", "31", "32"), class = "data.frame")
> >
> >Bob Green via R-help <r-help using r-project.org> escreveu (quinta,
> >8/10/2026 Ã (s) 11:19):
> > >
> > > Hello,
> > >
> > > I'm pretty rusty using R but wanted to compare
> > > four parameters measured in mm, in terms of the year an object was
> created.
> > >
> > > My problem is that where there are identical
> > > values, only one line is produced. For example,
> > > for the first parameter "tail",only five of a
> > possible eight lines are visible.
> > >
> > > The code and full dataset are below. I considered
> > > making trivial differences to identical values of
> > > a parameter to create difference,but no doubt
> > > there are more elegant or sophisticated options.
> > >
> > > Any advice is appreciated,
> > >
> > > Bob
> > >
> > > library(ggplot2)
> > > library(tidyr)
> > > library(readxl)
> > > DF <- read_excel("C:/Files/DataLong.xlsx")
> > > DF
> > >
> > >
> > > DF$Parameter <- factor(DF$Parameter, levels =
> > > c("Tail", "Tail_b", "Noseb", "Nose"))
> > >
> > >
> > > ggplot(DF, aes(x = Parameter, y =
> > Millimetres, color = Year, group = Year)) +
> > > geom_line(linewidth = 1) +
> > > geom_point(size = 2) + labs(title =
> > > "Parameters by Year", x = "Parameter", y = "Millimetres ($)") +
> > > theme_minimal()
> > >
> > > ##Data
> > >
> > >
> > > # A tibble: 32 × 3
> > > Parameter Millimetres Year
> > > <fct> <dbl> <chr>
> > > 1 Tail 0 2010-2012
> > > 2 Tail_b 0 2010-2012
> > > 3 Nose_b 20.3 2010-2012
> > > 4 Nose 74.9 2010-2012
> > > 5 Tail 0 2014
> > > 6 Tail_b 0 2014
> > > 7 Nose_b 14 2014
> > > 8 Nose 63.7 2014
> > > 9 Tail 11.2 2016
> > > 10 Tail_b 2.8 2016
> > > 11 Nose_b 16.3 2016
> > > 12 Nose 72.6 2016
> > > 13 Tail 0 2023
> > > 14 Tail_b 0 2023
> > > 15 Nose_b 17.1 2023
> > > 16 Nose 72.5 2023
> > > 17 Tail 11.3 2024
> > > 18 Tail_b 2.9 2024
> > > 19 Nose_b 16.9 2024
> > > 20 Nose 74.7 2024
> > > 21 Tail 28.1 2025C
> > > 22 Tail_b 4.9 2025C
> > > 23 Nose_b 6.8 2025C
> > > 24 Nose 37.7 2025C
> > > 25 Tail 25.9 2025B
> > > 26 Tail_b 5.2 2025B
> > > 27 Nose_b 11.2 2025B
> > > 28 Nose 68.1 2025B
> > > 29 Tail 30.2 2026
> > > 30 Tail_b 6.35 2026
> > > 31 Nose_b 15.1 2026
> > > 32 Nose 76.2 2026
> > >
> > > ______________________________________________
> > > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > PLEASE do read the posting guide
> > https://www.R-project.org/posting-guide.html
> > > and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> https://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
[[alternative HTML version deleted]]
More information about the R-help
mailing list