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\name{nowrapSpatialLines}
\alias{nowrapSpatialLines}
%- Also NEED an '\alias' for EACH other topic documented here.
\title{Split SpatialLines components at offset}
\description{
When recentering a world map, most often from the "Atlantic" view with longitudes with range -180 to 180, to the "pacific" view with longitudes with range 0 to 360, lines crossing the offset (0 for this conversion) get stretched horizonally. This function breaks Line objects at the offset (usually Greenwich), inserting a very small gap, and reassembling the Line objects created as Lines. The \pkg{rgeos} package is required to use this function.
}
\usage{
nowrapSpatialLines(obj, offset = 0, eps = rep(.Machine$double.eps^(1/2.5), 2))
}
%- maybe also 'usage' for other objects documented here.
\arguments{
\item{obj}{A Spatial Lines object}
\item{offset}{default 0, untried for other values}
\item{eps}{vector of two fuzz values, both default 2.5 root of double.eps}
}
\value{
A Spatial Lines object
}
\author{Roger Bivand}
\seealso{\code{\link[sp]{recenter-methods}}, \code{\link{nowrapSpatialPolygons}}}
\examples{
Sl <- SpatialLines(list(Lines(list(Line(cbind(sin(seq(-4,4,0.4)),
seq(1,21,1)))), "1")), proj4string=CRS("+proj=longlat +ellps=WGS84"))
summary(Sl)
if (require(rgeos)) {
nwSL <- nowrapSpatialLines(Sl)
summary(nwSL)
if(require(maps)) {
worldmap <- map("world", plot=FALSE)
worldmapLines <- map2SpatialLines(worldmap, proj4string=CRS("+proj=longlat +datum=WGS84"))
bbox(worldmapLines)
t0 <- nowrapSpatialLines(worldmapLines, offset=180)
bbox(t0)
}
}
}
\keyword{spatial}
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