Great-circle origin-destination flow map — flow

Draws great-circle arcs between country pairs from an origin-destination table (trade, migration, flights, remittances), resolving both endpoints to centroids automatically.

Usage

flow_map(data, from, to, weight = NULL, origin = "country.name", n = 50)

Arguments

data: An OD table.
from, to: The origin and destination country columns (unquoted; names or iso3c).
weight: Optional column controlling arc width/alpha (unquoted).
origin: How to read from/to (countrycode origin scheme).
n: Points per arc (smoothness).

Value

A ggplot object.

Examples

# \donttest{
od <- data.frame(from = c("China", "Germany"),
                 to = c("United States", "France"),
                 value = c(500, 200))
if (requireNamespace("maps", quietly = TRUE)) {
  flow_map(od, from, to, value)
}

# }