[R] How to use RColorBrewer in ggplot2?

[Luigi Marongiu]

Thank you! now it is clear.
Best regards,
Luigi

On Fri, Aug 15, 2025 at 1:31 PM Achim Zeileis <Achim.Zeileis using uibk.ac.at> wrote:
>
> Note that the RColorBrewer colors are also available in base R. The
> qualitative palettes are exactly the same as in the palette.colors()
> function:
>
> R> RColorBrewer::brewer.pal(4, "Paired")
> [1] "#A6CEE3" "#1F78B4" "#B2DF8A" "#33A02C"
>
> R> palette.colors(4, "Paired")
> [1] "#A6CEE3" "#1F78B4" "#B2DF8A" "#33A02C"
>
> For the sequential and diverging palettes, very close approximations using
> the HCL color model are available in hcl.colors():
>
> R> RColorBrewer::brewer.pal(9, "YlGnBu")
> [1] "#FFFFD9" "#EDF8B1" "#C7E9B4" "#7FCDBB" "#41B6C4" "#1D91C0" "#225EA8"
> [8] "#253494" "#081D58"
>
> R> hcl.colors(9, "YlGnBu", rev = TRUE)
> [1] "#FCFFDD" "#E3F8D4" "#BCE9C5" "#85D5B7" "#18BDB0" "#00A0AE" "#007EB3"
> [8] "#004C90" "#26185F"
>
> Best,
> Achim
>
> On Fri, 15 Aug 2025, Rui Barradas wrote:
>
> > Hello,
> >
> > You can create as many colors as you like with
> >
> > brewer.pal(n, name)
> >
> > where name is the palette name.
> > Then, combine with the other color.
> >
> > library(ggplot2)
> > library(RColorBrewer)
> >
> > brew_colrs <- brewer.pal(4, "Paired")
> > black <- "#000000"
> >
> > # set the names to the possible value of 'z'
> > colrs <- c(brew_cols, black) |> setNames(1:5)
> >
> > set.seed(50)
> > x <- runif(15, 0, 1)
> > df <- data.frame(x = x,
> >                y = x^2 + runif(15, 0, 1),
> >                z = rep(1:5, 3))
> >
> > ggplot(df, aes(x=x, y=y, colour=factor(z))) +
> >  geom_point(size=4) +
> >  scale_colour_manual(values = colrs)
> >
> >
> > Hope this helps,
> >
> > Rui Barradas
> >
> >
> >
> >
> > On 8/15/2025 5:42 AM, Luigi Marongiu wrote:
> >> Thank you, that worked fine.
> >> May I also ask how to create a vector of colors with RColorBrewer?
> >> Let's say I wanted to color z with 4 shade colors from the "Paired"
> >> palette, but then assign the fifth with a color of my choice, say
> >> "black", to distinguish clearly the fifth class.
> >> If I run
> >> ```
> >>> scale_fill_brewer(palette="BrBG")
> >> <ggproto object: Class ScaleDiscrete, Scale, gg>
> >>      aesthetics: fill
> >>      axis_order: function
> >>      break_info: function
> >>      break_positions: function
> >>      breaks: waiver
> >>      call: call
> >>      clone: function
> >>      dimension: function
> >>      drop: TRUE
> >>      expand: waiver
> >>      get_breaks: function
> >>      get_breaks_minor: function
> >>      get_labels: function
> >>      get_limits: function
> >>      get_transformation: function
> >>      guide: legend
> >>      is_discrete: function
> >>      is_empty: function
> >>      labels: waiver
> >>      limits: NULL
> >>      make_sec_title: function
> >>      make_title: function
> >>      map: function
> >>      map_df: function
> >>      n.breaks.cache: NULL
> >>      na.translate: TRUE
> >>      na.value: NA
> >>      name: waiver
> >>      palette: function
> >>      palette.cache: NULL
> >>      position: left
> >>      range: environment
> >>      rescale: function
> >>      reset: function
> >>      train: function
> >>      train_df: function
> >>      transform: function
> >>      transform_df: function
> >>      super:  <ggproto object: Class ScaleDiscrete, Scale, gg>
> >> ```
> >> while the help says "The brewer scales provide sequential, diverging
> >> and qualitative colour schemes".
> >> How can I generate 4 shades with RColorBrewer?
> >> Thanks.
> >>
> >> On Thu, Aug 14, 2025 at 10:00 AM Marttila Mikko
> >> <mikko.marttila using orionpharma.com> wrote:
> >>>
> >>> Hi Luigi,
> >>>
> >>> As you map z to colour, you need scale_colour_brewer, not the fill
> >>> version.
> >>> And to get discrete colours, you need to make z discrete. A separate group
> >>> mapping isn't needed in this case. Try this:
> >>>
> >>>      ggplot(df, aes(x=x, y=y, colour=factor(z))) +
> >>>        geom_point(size=4) +
> >>>        scale_colour_brewer(palette = "Paired")
> >>>
> >>> Best,
> >>>
> >>> Mikko
> >>>
> >>> -----Original Message-----
> >>> From: R-help <r-help-bounces using r-project.org> On Behalf Of Luigi Marongiu
> >>> Sent: Thursday, 14 August 2025 06:25
> >>> To: r-help <r-help using r-project.org>
> >>> Subject: [R] How to use RColorBrewer in ggplot2?
> >>>
> >>> Hello,
> >>> I would like to define a color range to custom color some plot,
> >>> specifically made in ggplot2 (but also for normal plots).
> >>> I have been trying to use RColorBrewer but I don't get any value out of
> >>> this function. I expected it would create a vector of color values, but I
> >>> must be missing something.
> >>> What is the correct you of this function?
> >>> Thank you.
> >>>
> >>> EXAMPLE
> >>> ```
> >>> set.seed(50)
> >>> df = data.frame(x = runif(15, 0, 1),
> >>>                  y = x^2 + runif(15, 0, 1),
> >>>                  z = rep(1:5, 3))
> >>> library(ggplot2)
> >>> library(RColorBrewer)
> >>> ggplot(df, aes(x=x, y=y, colour=z, group=z)) +
> >>>    geom_point(size=4) +
> >>>    scale_fill_brewer(palette = "Paired")
> >>> ```
> >>>
> >>>
> >>> --
> >>> Best regards,
> >>> Luigi
> >>>
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> >>>
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> >>
> >>
> >
> > ______________________________________________
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> > and provide commented, minimal, self-contained, reproducible code.
> >



-- 
Best regards,
Luigi