On one hand, I managed to plot something with this code:
ggplot(MSRmap, aes(long, lat, group = group))+
geom_polygon(aes(fill = Categoria), color = "white")+
facet_wrap(~Ano)
However, it gives these maps that don't show much. Only one country has the proper shape, while the others are crossed by white lines
Reproducible example:
data <- data.frame(
stringsAsFactors = FALSE,
Categoria = c("Estado-Parte","Estado-Parte",
"Estado-Parte","Estado-Parte","Estado-Parte",
"Estado-Associado","Estado-Parte","Estado-Associado",
"Estado-Parte","Estado-Parte"),
Ano = c(1991,1991,1991,1991,1996,
1996,1996,1996,1996,1996),
region = c("Argentina","Brazil",
"Paraguay","Uruguay","Argentina","Bolivia","Brazil","Chile",
"Paraguay","Uruguay")
)
world <- map_data("world")
MSRmap <- merge (world, data)