flowcontig: Builds an ordinal distance matrices from a spatial features background

Description

From a layer of areal spatial features, compute an ordinal distance matrice based on a k order criterion of adjacency or contiguity between origin and destination places . The result is a neighbourhood graph that can be used for filtering flow values before flow mapping (flowmap)

Usage

flowcontig(bkg, code, k, algo)

Arguments

bkg

a layer of areal spatial features (eg. the map background)

code

spatial areal features code

order of adjacency or contiguity between two areal spatial features

algo

algorithm to use for ordinal distance calculation. Default is "Dijkstra's" algorithm. See Details.

Value

a contiguity matrice with the k orders of adjacency

Details

The (k=1,2,...,k) order of adjacency or contiguity, of an areal spatial features background, is the number of spatial boundaries to be crossed between a couple of origin-destination (ODs) places. The k number can be assimilated to a shortest path between two pair of nodes Argument `k` is to enter the number k of the contiguity matrix to be constructed ; -kordre=1 : ODs places are adjacent, ie the flow have to cross only 1 boundary. -kordre=2 : ODs places are distant from 2 borders -kordre=k : ODs places are distant from k borders The function returns also the (k) number of the layer

Examples

Run this code

# NOT RUN {
library(cartograflow)
library(sf)
data(flowdata)
map <- st_read(system.file("shape/MGP_TER.shp", package = "cartograflow"))
graph_ckij_1 <- flowcontig(bkg = map, code = "EPT_NUM", k = 1, algo = "automatic")
# }
# NOT RUN {
flowmap(
  tab = graph_ckij_1,
  fij = "ordre", origin.f = "i", destination.f = "j",
  bkg = map, code = "EPT_NUM", nodes.X = "X", nodes.Y = "Y",
  filter = FALSE
)
# }