cartogram (version 0.2.2)

cartogram_ncont: Calculate Non-Contiguous Cartogram Boundaries

Description

Construct a non-contiguous area cartogram (Olson 1976).

Usage

cartogram_ncont(x, weight, k = 1, inplace = TRUE)
# S3 method for SpatialPolygonsDataFrame
cartogram_ncont(x, weight, k = 1, inplace = TRUE)
# S3 method for sf
cartogram_ncont(x, weight, k = 1, inplace = TRUE)

Value

An object of the same class as x with resized polygon boundaries

Arguments

x

SpatialPolygonDataFrame or an sf object

weight

Name of the weighting variable in x

k

Factor expansion for the unit with the greater value

inplace

If TRUE, each polygon is modified in its original place, if FALSE multi-polygons are centered on their initial centroid

References

Olson, J. M. (1976). Noncontiguous Area Cartograms. In The Professional Geographer, 28(4), 371-380.

Examples

library(maptools)
library(cartogram)
library(rgdal)
data(wrld_simpl)

# Remove uninhabited regions
afr <- spTransform(wrld_simpl[wrld_simpl$REGION==2 & wrld_simpl$POP2005 > 0,],
                   CRS("+init=epsg:3395"))

# Create cartogram
afr_nc <- cartogram_ncont(afr, "POP2005")

# Plot
plot(afr)
plot(afr_nc, add = TRUE, col = 'red')

# Same with sf objects
library(sf)

afr_sf = st_as_sf(afr)

afr_sf_nc <- cartogram_ncont(afr_sf, "POP2005")

plot(st_geometry(afr_sf))
plot(st_geometry(afr_sf_nc), add = TRUE, col = 'red')