pal2SpatialPolygons

0th

Percentile

Making SpatialPolygons objects from RArcInfo input

This function is used in making SpatialPolygons objects from RArcInfo input.

Keywords
spatial
Usage
pal2SpatialPolygons(arc, pal, IDs, dropPoly1=TRUE,
 proj4string=CRS(as.character(NA)))
Arguments
IDs

Unique character ID values for each output Polygons object; the input IDs can be an integer or character vector with duplicates, where the duplicates will be combined as a single output Polygons object

proj4string

Object of class "CRS"; holding a valid proj4 string

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 the numbers of arcs making up the boundary of each polygon

Value

The functions return a SpatialPolygons object

Aliases
  • pal2SpatialPolygons
Examples
# NOT RUN {
nc1 <- readShapePoly(system.file("shapes/sids.shp", package="maptools")[1], ID="FIPS")
plot(nc1)
text(coordinates(nc1), labels=row.names(nc1), cex=0.6)
if(require(maps)){
ncmap <- map("county", "north carolina", fill=TRUE, col="transparent",
 plot=FALSE)
IDs <- sapply(strsplit(ncmap$names, "[,:]"), function(x) x[2])
nc2 <- map2SpatialPolygons(ncmap, IDs)
plot(nc2)
text(coordinates(nc2), labels=row.names(nc2), cex=0.6)
}
if(require(RArcInfo)) {
td <- tempdir()
tmpcover <- paste(td, "nc", sep="/")
if (!file.exists(tmpcover)) e00toavc(system.file("share/co37_d90.e00",
 package="maptools")[1], tmpcover)
arc <- get.arcdata(td, "nc")
pal <- get.paldata(td, "nc")
pat <- get.tabledata(paste(td, "info", sep="/"), "NC.PAT")
sapply(pal[[2]], function(x) length(x[[1]]))
IDs <- paste(pat$ST[-1], pat$CO[-1], sep="")
nc3 <- pal2SpatialPolygons(arc, pal, IDs=IDs)
plot(nc3)
text(coordinates(nc3), labels=row.names(nc3), cex=0.6)
}
# }
Documentation reproduced from package maptools, version 0.9-8, License: GPL (>= 2)

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