[R] unique scale color ggplot2

[Thierry Onkelinx]

Don't use the cut() function.

ir. Thierry Onkelinx
Statisticus / Statistician

Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkelinx using inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be

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Op di 7 jul. 2020 om 18:42 schreef Rasmus Liland <jral using posteo.no>:

> On 2020-07-07 12:44 +0200, Thierry Onkelinx via R-help wrote:
> > Op di 7 jul. 2020 om 12:02 schreef Catalin Roibu <catalinroibu using gmail.com
> >:
> > >
> > > Dear R users,
> > >
> > > I want to create a plot for multiple
> > > sites and to keep the same color
> > > range scale (the correlation values
> > > range from -0.5 to 0.7 for all data,
> > > but I have sites with different min
> > > and max).
> > >
> > > I used this code:
> > > cols<-c("#0288D1", "#039BE5", "#03A9F4","#29B6F6", "#4FC3F7",
> "#FFCDD2",
> > > "#E57373", "#F44336", "#E53935", "#D32F2F", "#C62828", "#B71C1C")
> > > zCuts <-seq(-.5, 0.6, by = 0.1)
> > > p<-ggplot(df1, aes(x=as.factor(spei), y=as.factor(month), fill =
> cut(cor,
> > > zCuts))) +
> > >   geom_tile() +
> > >   scale_fill_manual(values=cols)
> > >
> > > but for each site the scale color is different.
> > >
> >
> > Dear Catalin,
> >
> > use scale_fill_gradient() and set fixed limits
> >
> > ggplot(df1, aes(x=as.factor(spei), y=as.factor(month), fill = cut(cor,
> > zCuts))) +
> >   geom_tile() +
> >   scale_fill_gradient(limits = c(-0.7, 0.7))
>
> Hmm ... what might df1 have looked like
> ... creating a df with columns spei,
> month, cor, and zCuts containing 1:5
> doesn't do the trick ...
>
>         df1 <-
>           data.frame(
>             spei=1:5,
>             month=1:5,
>             cor=1:5,
>             zCuts=1:5
>           )
>         cols <-
>           c("#0288D1", "#039BE5",
>             "#03A9F4","#29B6F6", "#4FC3F7",
>             "#FFCDD2", "#E57373", "#F44336",
>             "#E53935", "#D32F2F", "#C62828",
>             "#B71C1C")
>         zCuts <- seq(-.5, 0.6, by=0.1)
>         filename <- "/tmp/catalin1.png"
>         width <- 800
>         height <- 600
>         res <- 150
>         png(filename=filename, width=width, height=height, res=res)
>         mapping <- ggplot2::aes(
>           x = as.factor(spei),
>           y = as.factor(month),
>           fill = cut(cor, zCuts)
>         )
>         p <- ggplot2::ggplot(df1, mapping=mapping) +
>            ggplot2::geom_tile() +
>            ggplot2::scale_fill_gradient(limits = c(-0.7, 0.7))
>         #   ggplot2::scale_fill_manual(values=cols)
>         p
>         dev.off()
>
> ... which only produces the error
>
>         Error: Discrete value supplied to continuous scale
>         Execution halted
>
> V
>
> r
>
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