An origin-destination table as a matrix

Reshape a long bilateral table (trade, migration, flights, remittances) into a square origin x destination matrix on the ISO spine, with both country columns standardised. The natural input to a network analysis, and to country_weights()(type = "custom") – which is how "countries near each other in trade space" becomes a spatial weights object.

Usage

flow_matrix(
  data,
  from,
  to,
  weight = NULL,
  origin = "country.name",
  symmetric = FALSE,
  fill = 0
)

Arguments

data

An OD table.

from, to

The origin and destination country columns (unquoted).

weight

The flow column (unquoted). If omitted, every pair counts as 1.

origin

How to read from/to (default "country.name").

symmetric

If TRUE, add the transpose so the matrix is undirected (default FALSE).

fill

Value for pairs with no flow (default 0).

Value

A square numeric matrix with iso3c row and column names. Rows are origins, columns destinations.

See also

country_network(), flow_map(), country_weights()

Examples

od <- data.frame(
  from = c("China", "China", "Germany", "USA"),
  to   = c("USA", "Germany", "France", "Mexico"),
  value = c(500, 100, 80, 300)
)
flow_matrix(od, from, to, value)
#>     CHN DEU FRA MEX USA
#> CHN   0 100   0   0 500
#> DEU   0   0  80   0   0
#> FRA   0   0   0   0   0
#> MEX   0   0   0   0   0
#> USA   0   0   0 300   0