In r-tmap/tmap: Thematic Maps

knitr::opts_chunk$set(
  collapse = TRUE,
  out.width = "100%",
  dpi = 300,
  fig.width = 7.2916667,
  fig.height = 6,
  comment = "#>"
)
hook_output <- knitr::knit_hooks$get("output")
knitr::knit_hooks$set(output = function(x, options) {
   lines <- options$output.lines
   if (is.null(lines)) {
     return(hook_output(x, options))  # pass to default hook
   }
   x <- unlist(strsplit(x, "\n"))
   more <- "..."
   if (length(lines)==1) {        # first n lines
     if (length(x) > lines) {
       # truncate the output, but add ....
       x <- c(head(x, lines), more)
     }
   } else {
     x <- c(more, x[lines], more)
   }
   # paste these lines together
   x <- paste(c(x, ""), collapse = "\n")
   hook_output(x, options)
 })

library(tmap)
tmap_options(scale = 1)

mapsf

The R package mapsf is an excellent package for static thematic maps. It is similar to tmaps "plot" mode.

Map layers

mapsf also offers different map layers, but in contrast to tmap where these are generated by different functions (e.g. [tm_polygons()] and [tm_symbols()]), mapsf uses one function mf_map, where the map layer type is specified via the argument type.

Components

Map components, such as a title, compass, scale bar, and credits text, can be added with both packages. In mapsf these are mf_title, mf_arrow, mf_scale, and mf_credits respectively.

Different legends

The legends of mapsf and tmap are different:

• In tmap proportional symbols are always drawn next to each other whereas in mapsf they are drawn on top of each other. Also the the color legend for class intervals is different. Both are shown below.

Shadow layer

mapsf has an awesome layer type that tmap does not have (yet): mf_shadow, which draws a shadow under polygons. See last example below

Inset ('mini') map

In mapsf a inset map can be added via mf_inset_on. In tmap, inset maps can be added via the argument vp in the print function.

A special and very handy use case is mf_inset_on(x = "worldmap") where a globe is plotted with a red arrow that should the location of the main map. In tmap this feature is still only available via "view" mode with the function tm_minimap.

Styling and themes

Both packages offer styling options and themes. In both packages own styles can be created. However, tmap has much more styling options available. See mf_theme() and [tm_layout()].

Base vs grid graphics

A key difference between the "plot" mode of tmap and mapsf is that the "plot" mode of tmap makes use of the grid package (just like ggplot2) whereas mapsf uses base R graphics. This has some implications when combining plots.

Dependencies

mapsf has much less dependencies than tmap, so installation is faster.

Bubble map

An example of mapsf applied to the tmap dataset [NLD_muni].

library(mapsf)
mf_map(NLD_muni)
mf_map(NLD_muni, var = "population", type = "prop", leg_pos = "topright", add = TRUE)
mf_layout(
  title = "Population in Dutch municipalities in 2022",
  credits = "Statistics Netherlands (CBS)")

In tmap (using the same colors):

tm_shape(NLD_muni) +
  tm_polygons( "gray80") +
  tm_bubbles(fill = "tomato4", size = "population") +
tm_title("Population in Dutch municipalities in 2022") +
tm_credits("Statistics Netherlands (CBS)", position = c("left", "bottom"))

Increase the overall size of the bubbles:

tm_shape(NLD_muni) +
  tm_polygons( "gray80") +
tm_bubbles(
  fill = "tomato4", 
  size = "population",
  size.scale = tm_scale(values.scale = 5)) +
tm_title("Population in Dutch municipalities in 2022") +
tm_credits("Statistics Netherlands (CBS)", position = c("left", "bottom")) +
tm_compass() +
tm_scalebar()

Choropleth

mf_map(NLD_muni, var = "edu_appl_sci", type = "choro", leg_pos = "topright")
mf_layout(
  title = "Population share with (applied) university degree in 2022",
  credits = "Statistics Netherlands (CBS)")

In tmap, using similar specifications:

tm_shape(NLD_muni) +
  tm_polygons(
    fill = "edu_appl_sci",
    fill.scale = tm_scale_intervals(values = "carto.mint", style = "quantile", n = 9),
    fill.legend = tm_legend(reverse = TRUE)) +
tm_title("Population share with (applied) university degree in 2022") +
tm_credits("Statistics Netherlands (CBS)", position = c("left", "bottom")) +
tm_scalebar()

Shadow layer

mf_shadow(NLD_muni)
mf_map(NLD_muni, var = "edu_appl_sci", type = "choro", leg_pos = "topright", add = TRUE)

tmap does not has a similar layer function (yet), but it can be done with geometric manipulation in sf:

library(sf)
shadows = st_set_crs(st_geometry(NLD_muni) + c(2000, -2000), st_crs(NLD_muni))

tm_shape(shadows) +
  tm_fill("grey50") +
tm_shape(NLD_muni) +
  tm_polygons(
    fill = "edu_appl_sci",
    fill.scale = tm_scale_intervals(values = "carto.mint", style = "quantile", n = 9),
    fill.legend = tm_legend(reverse = TRUE)) 

r-tmap/tmap documentation built on Feb. 28, 2025, 7:54 a.m.