Use rotate in the package raster see for example: https://stat.ethz.ch/pipermail/r-sig-geo/2011-March/011155.html
Bart On 07/09/2013 11:59 PM, Jorge Molinos wrote: > Hello everybody, > > I have a raster that has longtitudes from 0 to 360 with the horizontal center > at 180 longtitude > > http://www.freeimagehosting.net/lr9rb > > Pre_CCSM_r > class : RasterLayer > dimensions : 395, 320, 126400 (nrow, ncol, ncell) > resolution : 1.125, 0.4294937 (x, y) > extent : 0.50001, 360.5, -79.43527, 90.21475 (xmin, xmax, ymin, ymax) > coord. ref. : +proj=longlat +datum=WGS84 > data source : in memory > names : layer > values : 271.2439, 303.2426 (min, max) > > I want to transform this to a new raster with -180, 180 longtitude range > centred at Greenwich meridian (0) for comparisons/analysis with other raster > files. I have tried cutting the original raster into two (using the meridian > 180 as cutting value) and piece them back together but got sort of a mosaic > raster instead > > http://www.freeimagehosting.net/h5bxo > >> lonlat <- data.frame(xyFromCell(Pre_CCSM_r, 1:ncell(Pre_CCSM_r))) >> lonlat <- cbind(lonlat, getValues(Pre_CCSM_r)) >> head(lonlat) > x y getValues(Pre_CCSM_r) > 1 1.06251 90 271.3698 > 2 2.18751 90 271.3698 > 3 3.31251 90 271.3698 > 4 4.43751 90 271.3698 > 5 5.56251 90 271.3698 > 6 6.68751 90 271.3698 > >> lolaA <- as.matrix(lonlat[lonlat$x>180,]) >> lolaB <- as.matrix(lonlat[lonlat$x<=180,]) >> mydata <- rbind(lolaA,lolaB) >> mydat <- matrix(mydata[,3], ncol=320,nrow=395,byrow=T) >> Pre_Had <- raster(mydat,xmn=-180, xmx=180, ymn=-90, >> ymx=90,crs="+proj=longlat +datum=WGS84") > > This is probably a very clumsy (obviously wrong) way of doing it so any > help/advice will be very much appreciated. > > Thanks!! > > Jorge > > > > > > > > > The Scottish Association for Marine Science (SAMS) is registered in Scotland > as a Company Limited by Guarantee (SC009292) and is a registered charity > (9206). SAMS has an actively trading wholly owned subsidiary company: SAMS > Research Services Ltd a Limited Company (SC224404). All Companies in the > group are registered in Scotland and share a registered office at Scottish > Marine Institute, Oban Argyll PA37 1QA. The content of this message may > contain personal views which are not the views of SAMS unless specifically > stated. Please note that all email traffic is monitored for purposes of > security and spam filtering. As such individual emails may be examined in > more detail. > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
