pal2SpatialPolygons
From maptools v0.9-9
by Roger Bivand
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
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)
}
# }
Community examples
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