input shapefile to build graph-using R
When using igraph to do network analysis- computing closeness for road
network, I confront these problems. I am trying to input shapefile data(line
and vertex), the R code is as follows:
library(igraph)
library(maptools)
pl <-
readShapeLines("H:/data/Beijing_NatrualRoads.shp",proj4string=CRS("+proj=Mercator_Auxiliary_Sphere
+datum=WGS84"))
pt <-
readShapePoints("H:/data/Beijing_NatrualRoads_ND_Junctions.shp",proj4string=CRS("+proj=Mercator_Auxiliary_Sphere
+datum=WGS84"))
Then errors occurs when trying to build graph using function
"graph.data.frame":
g <- graph.data.frame(pl, directed=FALSE, vertices=pt)
Error in graph.data.frame(pl, directed = FALSE, vertices = pt) : Duplicate vertex names Warning: In graph.data.frame(pl, directed = FALSE, vertices = pt) : In `d' `NA' elements were replaced with string "NA" Could anyone help me to solve these problems, thank you very much. -- View this message in context: http://r-sig-geo.2731867.n2.nabble.com/input-shapefile-to-build-graph-using-R-tp7587718.html Sent from the R-sig-geo mailing list archive at Nabble.com.