| polygonAdjacency {sharpshootR} | R Documentation |
This function utilizes the 'spdep' and 'igraph' packages to evaluate several measures of spatial connectivity.
polygonAdjacency(x, v='MUSYM', ...)
x |
a |
v |
name of the field in the attribute table to use when searching for 'common lines', see details |
... |
additional arguments passed to |
Pending.
A list object containing:
An integer vector of feature IDs, that share a common boundary and attribute v.commonLines. Sometimes referred to as "common soil lines".
A weighted adjacency matrix
D.E. Beaudette
## Not run:
##D library(spdep)
##D library(rgdal)
##D library(igraph)
##D library(sharpshootR)
##D
##D # load some data
##D x <- readOGR(dsn='L:/CA630/FG_CA630_OFFICIAL.gdb', layer='ca630_a', stringsAsFactors=FALSE)
##D
##D # remove NOTCOM, DA, and empty (non-NA) symbols
##D x <- x[which(! x$MUSYM ##D
##D
##D # compute spatial adjacency summary
##D res <- polygonAdjacency(x, v='MUSYM')
##D
##D # graphical check: slow for large number of features
##D plot(x)
##D plot(x[res$commonLines, ], col='red', add=TRUE)
##D
##D # save to SHP
##D writeOGR(x[res$commonLines, ], dsn='.',
##D layer='common-soil-lines', driver='ESRI Shapefile',
##D overwrite_layer=TRUE)
##D
##D # plot spatial adjacency information
##D par(mar=c(0,0,0,0))
##D plotSoilRelationGraph(res$adjMat,
##D vertex.scaling.factor = 1)
##D plotSoilRelationGraph(res$adjMat, spanning.tree='max',
##D edge.scaling.factor=0.1, vertex.scaling.factor=1)
## End(Not run)