centering map on Pacific Basin instead of Greenwich
On Wed, 30 Nov 2016, Chris Lusk wrote:
Hello all I'm making a global map of average leaf size in forests, using different colours to show dominance of different leaf size classes. The world map is of course centred on Greenwich (longitude zero) but none of my data are from Europe or Africa, so a map centred on the Pacific basin would look much better. In fact I'd like to cut Europe and Africa right out of the map (nothing personal about this!). Online I've seen several suggestions for re-centering the map, but they haven't worked for me. I would really appreciate suggestions about how to achieve this.
mapdata comes with world2Hires, which is Pacific centred. However, the
polygons are not split at 0, so wrap around if you need to fill. I think
your xlim= values are incorrect too, I get a Pacific basin from:
map("world2Hires", xlim=c(135, 290), ylim=c(-60,70), lty=1,
interior=FALSE)
but as lines not filled polygons.
Roger
My map code is pasted in below, and the data can be downloaded at http://sci.waikato.ac.nz/sites/clusk/DivrepNZ.csv cheers Chris ............ library(maps) library(mapdata) library(maptools) ###Get world map and fill landmasses to hide national borders map("worldHires", xlim=c(-165,180),ylim=c(-60,70),lty=1, col="gainsboro", fill=TRUE, border="gainsboro") ###Show axes with horizontal tick labels map.axes(cex.axis=0.75, las=1) ###Make axis titles title(xlab = "Longitude (degrees E)", ylab="Latitude (degrees S)") ##Get site location data to plot Data = read.csv("DivrepNZ.csv") Mesophyll = subset (Data, Size == "Mesophyll", select = c("Size", "ID", "lon", "lat")) Notophyll = subset (Data, Size == "Notophyll", select = c("Size", "ID", "lon", "lat")) Microphyll = subset (Data, Size == "Microphyll", select = c("Size", "ID", "lon", "lat")) Nanophyll = subset (Data, Size == "Nanophyll", select = c("Size", "ID", "lon", "lat")) points(Mesophyll[,"lon"], Mesophyll[,"lat"],pch=15, cex=0.6, col="red3") points(Notophyll[,"lon"], Notophyll[,"lat"], pch=15, cex=0.6, col="orange") points(Microphyll[,"lon"], Microphyll[,"lat"], pch=15, cex=0.6, col="green3") points(Nanophyll[,"lon"], Nanophyll[,"lat"], pch=15, cex=0.6, col="blue") *- - - - - - -*Chris Lusk Environmental Research Institute University of Waikato Hamilton New Zealand Senior Editor, *New Zealand Journal of Botany* [[alternative HTML version deleted]]
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Roger Bivand Department of Economics, Norwegian School of Economics, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 91 00 e-mail: Roger.Bivand at nhh.no http://orcid.org/0000-0003-2392-6140 https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en http://depsy.org/person/434412