Advice on reproducible map_coloring?

[MatthieuStigler]

Hi

I was wondering whether it is possible to have a replicable output with map_coloring, i.e. that is constant across calls? This is particularly useful when one is trying to use testhat snapshots.

I realize that setting minimize=TRUE avoids the call to sample(), so that is already a workaround. Should one want more colors than the strict minimum, the output seems to change each time. Do you see an easy way to add maybe a seed argument?

Thanks!

library(tmaptools)
packageVersion("tmap")
#> [1] '3.3.2'
packageVersion("tmaptools")
#> [1] '3.1.1'
library(tmap)

data(World)

color <- map_coloring(World, palette="Pastel2")
color2 <- map_coloring(World, palette="Pastel2")
all.equal(color, color2)
#> [1] "152 string mismatches"


color <- map_coloring(World, palette="Pastel2", minimize=TRUE)
color2 <- map_coloring(World, palette="Pastel2", minimize=TRUE)
all.equal(color, color2)
#> [1] TRUE

[mtennekes]

As a solution/workaround, the user can also set the seed:

set.seed(123)
color <- map_coloring(World, palette="Pastel2")
set.seed(123)
color2 <- map_coloring(World, palette="Pastel2")
all.equal(color, color2)
#> [1] TRUE

[MatthieuStigler]

strange, I had tried this, but if doesn't work for me...

library(tmaptools)
packageVersion("tmap")
#> [1] '3.3.2'
packageVersion("tmaptools")
#> [1] '3.1.1'
library(tmap)
data(World)

set.seed(123)
color <- map_coloring(World, palette="Pastel2")
set.seed(123)
color2 <- map_coloring(World, palette="Pastel2")
head(color)
#> [1] "#F1E2CC" "#FDCDAC" "#FFF2AE" "#FDCDAC" "#F4CAE4" "#B3E2CD"
head(color2)
#> [1] "#FFF2AE" "#F4CAE4" "#B3E2CD" "#FDCDAC" "#B3E2CD" "#FFF2AE"
all.equal(color, color2)
#> [1] "161 string mismatches"

^{Created on 2022-02-24 by the reprex package (v2.0.1)}

[mtennekes]

Is this still an issue with the latest dev versions of tmap and tmaptools @MatthieuStigler ?

[MatthieuStigler]

not anymore using the latest CRAN versions, thanks for addressing this!

On the other hand, there is a warning now:

This function is deprecated; please use cols4all::c4a() instead

Seems to come from get_brewer_pal(), is there a reason it uses a message instead of the standard .Deprecated (with consequence one doesn't know which function is deprecated when calling map_coloring)?

library(tmaptools)
packageVersion("tmap")
#> [1] '4.1'
packageVersion("tmaptools")
#> [1] '3.2'
library(tmap)
data(World)

set.seed(123)
color <- map_coloring(World, palette="Pastel2")
#> This function is deprecated; please use cols4all::c4a() instead
set.seed(123)
color2 <- map_coloring(World, palette="Pastel2")
#> This function is deprecated; please use cols4all::c4a() instead
head(color)
#> [1] "#B3E2CD" "#B3E2CD" "#F1E2CC" "#F4CAE4" "#FFF2AE" "#F4CAE4"
head(color2)
#> [1] "#B3E2CD" "#B3E2CD" "#F1E2CC" "#F4CAE4" "#FFF2AE" "#F4CAE4"
all.equal(color, color2)
#> [1] TRUE

^{Created on 2025-07-08 with reprex v2.1.1}

[mtennekes]

Thx for bringing this up @MatthieuStigler
Didn't know the .Deprecated function to be honest. Should have been better.

In the next update of tmaptools, I'll remove all color-related functions, which have been deprecated for a while (albeit not via .Deprecated), i..e replaced by cols4all. However, map_coloring will still exist, but only via indices (instead of palette colors). The new syntax will is:

color <- c4a("brewer.pastel2")[map_coloring(World)]

I'll inform the users via a message.