Dear all, I am encountering an issue related to an old thread from 2011 (pasted below), and would like to know if someone could provide sample code for when one wishes to manually delete contiguity between two points, while retaining all other contiguities for those points. I am relatively new with R, so I apologize if this is obvious! Thank you, Katie Dear Alexander, Following your suggestion I have used this syntax and works perfectly: x.nb[[67]] = as.integer(sort(c(43,53))) x.nb[[43]] = as.integer(sort(c(x.nb[[43]],67))) x.nb[[53]] = as.integer(sort(c(x.nb[[53]],67))) Thank you very much for your help! Marc 2011/5/17 Alexander Werner <werner at wirtschaft.uni-kassel.de<https://stat.ethz.ch/mailman/listinfo/r-sig-geo>>:
Dear Marc,
facing a similar problem I choose to correct the NB object manually:
NBDKR439[[350]]= as.integer(sort(c(NBDKR439[[350]],362)))
NBDKR439[[362]]= as.integer(350)
Hope this helps,
Alexander
Am 16.05.2011 19:01, schrieb Marc Mar? Dell'Olmo:
Dear all,
I have a cartography with an island, i.e. a polygon that doesn't share
border with other polygons (CODIGO=3120104012). I would like to
manually assign two areas (CODIGO=3120103024 and CODIGO=3120103014) as
a neighborhood areas of this island with the edit.nb function, and
after that to obtain the neighborhood matrix. I have followed this
syntax and I don't understand why the summary(x.nb2) still shows one
region with no link...
If it helps, you can download the map at:
Thank you very much,
Marc
map<-readShapePoly("F:/map/map.shp")
map<-map[order(map$CODIGO),]
x.nb<-poly2nb(map)
summary(x.nb)
#Neighbour list object:
#Number of regions: 122
#Number of nonzero links: 724
#Percentage nonzero weights: 4.864284
#Average number of links: 5.934426
#1 region with no links:
#66
#Link number distribution:
#0 2 3 4 5 6 7 8 9 10 11 12 14
#1 1 7 19 22 31 21 12 2 2 2 1 1
#1 least connected region:
#101 with 2 links
#1 most connected region:
#29 with 14 links
nb<- x.nb
which(card(nb) == 0)
attr(nb, "region.id")[which(card(nb) == 0)]
x.nb2<- edit.nb(x.nb,polys=map)
#> x.nb2<- edit.nb(x.nb,polys=map)
#Identifying contiguity for deletion ...
#No contiguity between chosen points
#Add contiguity? (y/n) y
#added contiguity between point 53 and 67
#Options: quit[q] refresh[r] continue[c] c
#Identifying contiguity for deletion ...
#No contiguity between chosen points
#Add contiguity? (y/n) y
#added contiguity between point 43 and 67
#Options: quit[q] refresh[r] continue[c] q
summary(x.nb2)
#Neighbour list object:
#Number of regions: 122
#Number of nonzero links: 726
#Percentage nonzero weights: 4.877721
#Average number of links: 5.95082
#1 region with no links:
#66
#Non-symmetric neighbours list
#Link number distribution:
#0 2 3 4 5 6 7 8 9 10 11 12 14
#1 1 7 18 22 32 21 12 2 2 2 1 1
#1 least connected region:
#101 with 2 links
#1 most connected region:
#29 with 14 links
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Dipl.-?k. Alexander Werner
_______________________________________________
Universit?t Kassel
Fachbereich Wirtschaftswissenschaften
Fachgebiet Empirische Wirtschaftsforschung
Nora-Platiel-Str. 4
34109 Kassel
Tel.: 0561 / 804 - 3044
werner at wirtschaft.uni-kassel.de<https://stat.ethz.ch/mailman/listinfo/r-sig-geo>
_______________________________________________
Katie Wheeler-Martin, MPH
Senior Data Analyst
Department of Surgery
New York University School of Medicine
550 First Avenue
New York, NY 10016
Office: 1.212.263.6308
katherine.wheeler-martin at nyumc.org<mailto:katherine.wheeler-martin at nyumc.org>
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