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cartogram: Create Cartograms with R

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CRAN status R-CMD-check CRAN Downloads

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Construct a continuous area cartogram by a rubber sheet distortion algorithm (Dougenik et al. 1985), non-contiguous Area Cartograms (Olson 1976), and non-overlapping Circles Cartogram (Dorling el al. 1996) in R.

Installation

You can install the cartogram package from CRAN as follows:

install.packages("cartogram")

To upgrade to the latest development version of cartogram, install the package devtools and run the following command:

devtools::install_github("sjewo/cartogram")

Examples

Continuous Area Cartogram

library(cartogram)
library(sf)
#> Linking to GEOS 3.11.0, GDAL 3.5.3, PROJ 9.1.0; sf_use_s2() is TRUE
library(tmap)

data("World")

# keep only the african continent
afr <- World[World$continent == "Africa", ]

# project the map
afr <- st_transform(afr, 3395)

# construct cartogram
afr_cont <- cartogram_cont(afr, "pop_est", itermax = 5)

# plot it
tm_shape(afr_cont) + tm_polygons("pop_est", style = "jenks") +
  tm_layout(frame = FALSE, legend.position = c("left", "bottom"))

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Non-contiguous Area Cartogram

Many thanks to @rCarto and @neocarto for contributing the code!

# construct cartogram
afr_ncont <- cartogram_ncont(afr, "pop_est")

# plot it
tm_shape(afr) + tm_borders() +
  tm_shape(afr_ncont) + tm_polygons("pop_est", style = "jenks") +
  tm_layout(frame = FALSE, legend.position = c("left", "bottom"))

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Non-Overlapping Circles Cartogram

Many thanks to @rCarto for contributing the code!

# construct cartogram
afr_dorling <- cartogram_dorling(afr, "pop_est")

# plot it
tm_shape(afr) + tm_borders() +
  tm_shape(afr_dorling) + tm_polygons("pop_est", style = "jenks") +
  tm_layout(frame = FALSE, legend.position = c("left", "bottom"))

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References