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sp (version 0.9-78)

nowrapSpatialLines: 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. A similar function for polygons is found in the spgpc package.

Usage

nowrapSpatialLines(obj, offset = 0, eps = rep(.Machine$double.eps, 2))

Arguments

obj
A Spatial Lines object
offset
default 0, untried for other values
eps
vector of two fuzz values, both default double.eps

Value

  • A Spatial Lines object

Examples

Run this code
Sl <- SpatialLines(list(Lines(list(Line(cbind(sin(seq(-4,4,0.4)), seq(1,21,1)))), "1")), proj4string=CRS("+proj=longlat"))
summary(Sl)
nwSL <- nowrapSpatialLines(Sl)
summary(nwSL)

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