flows (version 1.1.1)

domflows: Dominant Flows Selection

Description

Dominant flows selection.

Usage

domflows(mat, w, k)

Arguments

mat

A square matrix of flows.

w

A vector of units weigths (sum of incoming flows, sum of outgoing flows...).

k

A threshold (see 'Details').

Value

A boolean matrix of selected flows.

Details

This function selects which flow (fij or fji) must be kept. If the ratio weight of destination (wj) / weight of origin (wi) is greater than k, then fij is selected and fji is not. This function can perform the second criterion of the Nystuen & Dacey's dominants flows analysis. As the output is a boolean matrix, use element-wise multiplication to get flows intensity.

References

J. Nystuen & M. Dacey, 1961, "A Graph Theory Interpretation of Nodal Regions.", Papers and Proceedings of the Regional Science Association, 7:29-42.bt

See Also

firstflows, firstflowsg, plotDomFlows, plotMapDomFlows

Examples

# Import data
data(nav)
myflows <- prepflows(mat = nav, i = "i", j = "j", fij = "fij")

# Remove the matrix diagonal
diag(myflows) <- 0

# Select the dominant flows (incoming flows criterion)
flowSel <- domflows(mat = myflows, w = colSums(myflows), k = 1)
statmat(mat = myflows * flowSel, output = "none")