The dorling algorithm creates a non-contiguous cartogram by shifting circles to alleviate overlap, while roughly maintaining geographic proximity.
aec_carto_f(
aec_data_sub,
polygon.vertex = 6,
name.text = TRUE,
dist.ratio = dist.ratio,
iteration = 100,
xlab = "",
ylab = "",
...
)Arguments
- aec_data_sub
subset of data with centroids of electoral divisions
- polygon.vertex
The number of vertice of the circle. Default to be 100. If polygon.vertex=4 then diamonds applies. If polygon.vertex=6, then hexagon applies.
- name.text
whether to print the region names on the circles or polygons.
- dist.ratio
The threshold to determine whether an attract force is added. It is applied to the ratio of the distance between two centroids and the sum of the two radii.
- iteration
The limit of the number of iterations. Default to be 9999.
- xlab
Label for dorling x axis, intermediate drawing
- ylab
Label for dorling y axis, intermediate drawing
- ...
arguments to dorling function
Examples
library(dplyr)
library(ggplot2)
nat_map16 <- nat_map_download(2016)
nat_data16 <- nat_data_download(2016)
nat_data16 <- nat_data16 %>% select(-c(x,y)) # remove existing cartogram coordinates
adelaide <- aec_extract_f(nat_data16, ctr=c(138.6, -34.9), expand=c(2,3))
adelaide_carto <- aec_carto_f(adelaide) %>% rename(id=region)
ggplot(data=nat_map16) +
geom_path(aes(x=long, y=lat, group=group, order=order),
colour="grey50") +
geom_point(data=adelaide_carto, aes(x=x, y=y), size=4, alpha=0.4,
colour="#f0027f") +
xlim(c(136, 140)) + ylim(-36, -33) +
coord_equal()
#> Warning: Ignoring unknown aesthetics: order
#> Warning: Removed 35868 rows containing missing values (`geom_path()`).
#> Warning: Removed 1 rows containing missing values (`geom_point()`).
adelaide_all <- merge(adelaide, adelaide_carto, by="id")
ggplot(data=nat_map16) +
geom_path(aes(x=long, y=lat, group=group, order=order),
colour="grey50") +
geom_point(data=adelaide_all, aes(x=long_c, y=lat_c), size=2, alpha=0.4,
colour="#f0027f") +
geom_point(data=adelaide_all, aes(x=x, y=y), size=2, alpha=0.4,
colour="#f0027f") +
geom_segment(data=adelaide_all,
aes(x=long_c, xend=x, y=lat_c, yend=y), colour="#f0027f") +
xlim(c(136, 140)) + ylim(-37, -33) +
coord_equal()
#> Warning: Ignoring unknown aesthetics: order
#> Warning: Removed 35855 rows containing missing values (`geom_path()`).
#> Warning: Removed 1 rows containing missing values (`geom_point()`).
#> Warning: Removed 1 rows containing missing values (`geom_point()`).
#> Warning: Removed 1 rows containing missing values (`geom_segment()`).
