# recenter-methods: Methods for Function recenter in Package 'sp' In sp: Classes and Methods for Spatial Data

## Description

Methods for function `recenter` in package sp to shift or re-center geographical coordinates for a Pacific view. All longitudes < 0 are added to 360, to avoid for instance parts of Alaska being represented on the far left and right of a plot because they have values straddling 180 degrees. In general, using a projected coordinate reference system is to be preferred, but this method permits a geographical coordinate reference system to be used. This idea was suggested by Greg Snow, and corresponds to the two world representations in the maps package.

## Methods

obj = "SpatialPolygons"

recenter a SpatialPolygons object

obj = "Polygons"

recenter a Polygons object

obj = "Polygon"

recenter an Polygon object

obj = "SpatialLines"

recenter a SpatialLines object

obj = "Lines"

recenter a Lines object

obj = "Line"

recenter an Line object

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32``` ```crds <- matrix(c(179, -179, -179, 179, 50, 50, 52, 52), ncol=2) SL <- SpatialLines(list(Lines(list(Line(crds)), "1")), CRS("+proj=longlat +ellps=WGS84")) bbox(SL) SLr <- recenter(SL) bbox(SLr) rcrds <- rbind(crds, crds[1,]) SpP <- SpatialPolygons(list(Polygons(list(Polygon(rcrds)), ID="r1")), proj4string=CRS("+proj=longlat +ellps=WGS84")) bbox(SpP) SpPr <- recenter(SpP) bbox(SpPr) opar <- par(mfrow=c(1,2)) plot(SpP) plot(SpPr) par(opar) crds <- matrix(c(-1, 1, 1, -1, 50, 50, 52, 52), ncol=2) SL <- SpatialLines(list(Lines(list(Line(crds)), "1")), CRS("+proj=longlat +ellps=WGS84")) bbox(SL) SLr <- recenter(SL) bbox(SLr) rcrds <- rbind(crds, crds[1,]) SpP <- SpatialPolygons(list(Polygons(list(Polygon(rcrds)), ID="r1")), proj4string=CRS("+proj=longlat +ellps=WGS84")) bbox(SpP) SpPr <- recenter(SpP) bbox(SpPr) opar <- par(mfrow=c(1,2)) plot(SpP) plot(SpPr) par(opar) ```

sp documentation built on Feb. 29, 2020, 1:07 a.m.