sp (version 0.7-5)

as.SpatialRings.SringsList: Making SpatialRings objects

Description

These functions show how SpatialRings objects may be built from data from shapefiles, from the maps package, and from ArcInfo e00 files.

Usage

as.SpatialRings.SringsList(Srl)
as.SpatialRings.Shapes(shapes, IDs, proj4string=CRS(as.character(NA)))
as.SpatialRings.map(map, IDs, proj4string=CRS(as.character(NA)))
as.SpatialRings.pal(arc, pal, IDs, dropPoly1=TRUE, proj4string=CRS(as.character(NA)))

Arguments

Srl
A list of Srings objects
shapes
The Shapes component of a Map object as read by read.shape
IDs
Unique character ID values for each output Srings object; the input IDs can be an integer or character vector with duplicates, where the duplicates will be combined as a single output Srings object
proj4string
Object of class "CRS"; holding a valid proj4 string
map
Object returned by map containing polygon boundaries
arc
Object returned by get.arcdata
pal
Object returned by get.paldata
dropPoly1
Should the first polygon in the AVC or e00 data be dropped; the first polygon is typically the compound boundary of the whole dataset, and can be detected by looking at the relative lengths of the list components in the second component of pal, which are

Value

  • The functions return a SpatialRings object

Examples

Run this code
library(maptools)
nc.shp <- read.shape(system.file("shapes/sids.shp", package="maptools")[1])
data(ncshp)
nc1 <- as.SpatialRings.Shapes(nc.shp$Shapes, as.character(nc.shp$att.data$FIPS))
plotSpatialRings(nc1)
invisible(text(getSRSringsLabptSlots(nc1), labels=getSRSringsIDSlots(nc1), cex=0.6))
library(maps)
ncmap <- map("county", "north carolina", fill=TRUE, col="transparent", plot=FALSE)
data(ncmap)
IDs <- sapply(strsplit(ncmap$names, ","), function(x) x[2])
nc2 <- as.SpatialRings.map(ncmap, IDs)
plotSpatialRings(nc2)
invisible(text(getSRSringsLabptSlots(nc2), labels=getSRSringsIDSlots(nc2), cex=0.6))
library(RArcInfo)
fl <- "http://www.census.gov/geo/cob/bdy/co/co90e00/co37_d90_e00.zip"
download.file(fl, "co37_d90_e00.zip")
e00 <- zip.file.extract("co37_d90.e00", "co37_d90_e00.zip")
e00toavc(e00, "nc")
arc <- get.arcdata(".", "nc")
pal <- get.paldata(".", "nc")
pat <- get.tabledata("info", "NC.PAT")
data(co37_d90_arc)
data(co37_d90_pal)
sapply(pal[[2]], function(x) length(x[[1]]))
data(co37_d90_pat)
IDs <- paste(pat$ST[-1], pat$CO[-1], sep="")
nc3 <- as.SpatialRings.pal(arc, pal, IDs=IDs)
plotSpatialRings(nc3)
invisible(text(getSRSringsLabptSlots(nc3), labels=getSRSringsIDSlots(nc3), cex=0.6))

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