#' @title Computes an ordinal distance matrices based on geographical background
#' @description
#' From a geographical background, compute an ordinal distance matrice based on a k-contiguity.
#' The result is a neighbourhood graph that can be used for filtering flow values beor flow mapping (\link{flowmap})
#' @param fdc is the map background file (ie. a shapefile of polygons)
#' @param code identifiant
#' @param ordre number of borders to cross between origin and destination place. See details.
#' @return a (k) contiguity matrice with the (k) contiguity measures
#' @details
#' Contiguity is in terms of the (k=1,2,4) number of spatial boundaries to be crossed between
#' a place of origin and a place of destination
#' -- ordre=1 is when the flow have to cross only 1 boundary
#' -- ordre=2 is when the origin-destinations places are distant from 2 borders
#' -- ordre=4 is when the origin-destinations places are distant from 4 borders
#' @export
#' @importFrom rgeos gIntersects
flowcontig<-function(fdc,code,ordre){
ordre1<-function(fdc,code){
carte<- readOGR(fdc,verbose = FALSE)
contig<-gIntersects(carte, byid = TRUE, prepared=TRUE)
row.names(contig)<-carte@data[,code]
colnames(contig)<-carte@data[,code]
for (i in 1:nrow(contig))
for (j in 1:ncol(contig))
{if (contig[i,j]==TRUE) {contig[i,j]<-1}
if (contig[i,i]!=0) {contig[i,i]<-0}
}
tab <-flowtabmat(contig,matlist = "L")
colnames(tab)<-c("CODE_i","CODE_j","cij")
ordre_1<-tab[tab[,"cij"]!=0,]
}
ordre2<-function(c1){
CKij_1<-c1
CKij_1$CODE_i1<-0
CKij_1$CODE_j1<-0
CKij_1$CODE_j2<-0
CKij_1$cij2<-0
for (k in 1:nrow(CKij_1))
{
if (CKij_1$cij[k]==1)
{
col_i<-CKij_1$CODE_i[k]
col_j<-CKij_1$CODE_j[k]
for (v in 1:nrow(CKij_1)){
if (CKij_1$CODE_i[v]==col_j && CKij_1$CODE_i[v]!=CKij_1$CODE_j[v]){
CKij_1$CODE_i1[k]<-col_i
CKij_1$CODE_j1[k]<-col_j
CKij_1$CODE_j2[k]<- CKij_1$CODE_j[v]
CKij_1$cij2[k]<-2}
}
}
}
ordre_2<-data.frame(CKij_1$CODE_i,CKij_1$CODE_j2,CKij_1$cij2)
names(ordre_2) = c("i", "j2","cij2")
for (z in 1:nrow(ordre_2))
if (ordre_2$i[z] == ordre_2$j2[z]) ordre_2$cij2[z]<-0
ordre_2<-ordre_2[ordre_2[,"cij2"]!=0,]
}
ordre4<-function(c2){
ordre_2<-c2
ordre_2$CODE_i<-0
ordre_2$CODE_j2<-0
ordre_2$CODE_j4<-0
ordre_2$cij4<-0
for (k in 1:nrow(ordre_2)){
if (ordre_2$cij2[k]==2)
{
col_i4<-ordre_2$i[k]
col_j4<-ordre_2$j2[k]
for (v in 1:nrow(ordre_2))
{
if (ordre_2$i[v]==col_j4 && ordre_2$i[v]!=ordre_2$j2[v]){
ordre_2$CODE_i[k]<-col_i4
ordre_2$CODE_j2[k]<-col_j4
ordre_2$CODE_j4[k]<-ordre_2$j2[v]
ordre_2$cij4[k]<-4}
}
}
}
ordre_4<-data.frame(ordre_2$CODE_i,ordre_2$CODE_j4,ordre_2$cij4)
names(ordre_4) = c("i", "j4","cij4")
for (z in 1:nrow(ordre_4))
if (ordre_4$i[z] == ordre_4$j4[z]) ordre_4$cij4[z]<-0
ordre_4<-ordre_4[ordre_4[,"cij4"]!=0,]
}
if (ordre=="1"){
tab1<-ordre1(fdc,code)
colnames(tab1)<-c("i","j","ydata")
return(tab1)}
if (ordre=="2"){
tab1<-ordre1(fdc,code)
tab2<-ordre2(tab1)
colnames(tab2)<-c("i","j","ydata")
return(tab2)}
if (ordre=="4"){
tab1<-ordre1(fdc,code)
tab2<-ordre2(tab1)
tab4<-ordre4(tab2)
colnames(tab4)<-c("i","j","ydata")
return(tab4)}
}
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