# cartogram_cont: Calculate Contiguous Cartogram Boundaries In cartogram: Create Cartograms with R

 cartogram_cont R Documentation

## Calculate Contiguous Cartogram Boundaries

### Description

Construct a continuous area cartogram by a rubber sheet distortion algorithm (Dougenik et al. 1985)

### Usage

``````cartogram_cont(
x,
weight,
itermax = 15,
maxSizeError = 1.0001,
threshold = 0.05,
verbose = FALSE
)

## S3 method for class 'SpatialPolygonsDataFrame'
cartogram_cont(
x,
weight,
itermax = 15,
maxSizeError = 1.0001,
threshold = 0.05,
verbose = FALSE
)

## S3 method for class 'sf'
cartogram_cont(
x,
weight,
itermax = 15,
maxSizeError = 1.0001,
threshold = 0.05,
verbose = FALSE
)
``````

### Arguments

 `x` a polygon or multiplogyon sf object `weight` Name of the weighting variable in x `itermax` Maximum iterations for the cartogram transformation, if maxSizeError ist not reached `maxSizeError` Stop if meanSizeError is smaller than maxSizeError `prepare` Weighting values are adjusted to reach convergence much earlier. Possible methods are "adjust", adjust values to restrict the mass vector to the quantiles defined by threshold and 1-threshold (default), "remove", remove features with values lower than quantile at threshold, "none", don't adjust weighting values `threshold` Define threshold for data preparation `verbose` print meanSizeError on each iteration

### Value

An object of the same class as x

### References

Dougenik, J. A., Chrisman, N. R., & Niemeyer, D. R. (1985). An Algorithm To Construct Continuous Area Cartograms. In The Professional Geographer, 37(1), 75-81.

### Examples

``````library(sf)
library(cartogram)

nc = st_read(system.file("shape/nc.shp", package="sf"), quiet = TRUE)

# transform to NAD83 / UTM zone 16N
nc_utm <- st_transform(nc, 26916)

# Create cartogram
nc_utm_carto <- cartogram_cont(nc_utm, weight = "BIR74", itermax = 5)

# Plot
par(mfrow=c(2,1))
plot(nc[,"BIR74"], main="original", key.pos = NULL, reset = FALSE)
plot(nc_utm_carto[,"BIR74"], main="distorted", key.pos = NULL, reset = FALSE)

``````

cartogram documentation built on May 31, 2023, 6:16 p.m.