migration.gini.col {migration.indices}

Columns Gini Index

Description

The Columns Gini index concentrates on the "relative extent to which the destination selections of in-migrations are spatially focused":

G^T_R = \frac{\sum_j \sum_{i \neq j} \sum_{g \neq i,j} | M_{ij} - M_{gj} | }{ (2n(n-1)-1) \sum_i \sum_{j \neq i} M_{ij}}

This implementation solves the above formula by computing the dist matrix for each columns.

Usage

migration.gini.col(m)

Arguments

m

migration matrix

Value

A number between 0 and 1 where 0 means no spatial focusing and 1 shows maximum focusing.

References

• David A. Plane and Gordon F. Mulligan (1997) Measuring Spatial Focusing in a Migration System. Demography 34, 251–262

See Also

migration.gini.row migration.gini.col.standardized

Examples

data(migration.hyp)
migration.gini.col(migration.hyp)  # 0.05555556
migration.gini.col(migration.hyp2) # 0.04166667