====== Neighbors ======

We use the solution from [[notes:net:shape]].

Requires package ''spdep''.
<code>
> shp2Pajek <- function(pl,file="neighbors.net",name=0){
+   library(spdep); cat("shp2Pajek:",date(),"/"); flush.console()
+   nbr<-poly2nb(pl,queen=FALSE); nbq<-poly2nb(pl,queen=TRUE)
+   n <- length(nbr); L <- card(nbr)
+   xy <- coordinates(pl)
+   IDs <- as.character(if(name>0) pl[[name]] else 1:n)
+   net <- file(file,"w")
+   cat("% shp2Pajek:",date(),"\n*vertices",n,"\n",file=net)
+   for(i in 1:n) cat(i,' "',IDs[i],'" ',xy[i,1],' ',xy[i,2],' 0.5\n',sep='',file=net)
+   cat('*edgeslist  :1 "rook"\n',file=net)
+   for(i in 1:n) if(L[i]>0) cat(i,nbr[[i]],"\n",file=net)
+   cat('*edgeslist  :2 "queen"\n',file=net)
+   L <- card(nbq)-card(nbr)
+   for(i in 1:n) if(L[i]>0) cat(i,setdiff(nbq[[i]],nbr[[i]]),"\n",file=net)
+   cat(date(),"\n"); close(net)
+ }
</code>

<code>
> setwd("C:/Users/batagelj/Documents/papers/2018/CRoNoS/shape/Europe")
> library(maptools)
> Eu <- readShapeSpatial("Europe.shp") 
> names(Eu)
[1] "NAME"      "ORGN_NAME"
> shp2Pajek(Eu,name="NAME",file="Europe0.net")
</code>

The neighbors relation obtained from the shape file (black edges) forms a disconnected graph. To make it connected we have to manually add "sea borders" (blue edges). I also noticed that three countries are missing in the network: Cyprus, Vatican and
Kosovo. I added them manually (red edges for Kosovo and Vatican). Adding Kosovo cuts the edge (Serbia : Albania).

{{notes:da:pics:europenet.png}}

Because of strong relations we added an sea-edge (Faeroe Islands : Danmark).

\\

[[notes:da:ciaeu|Back to CIA Europe data]]