Hi folks,

Long time lurker, first time inquirer.  I'm sorry -- I'm pretty sure this
is basic, but I'm brand new to this software.  I'm fairly experienced with
Arc*, but am trying to learn R for faster visualization production.
Apologies if this is a simple question, but this didn't come up in a search
of the archives, save for one unanswered thread.

I'm looking to reproject a RasterLayer in +latlong into a Eckert IV
pseudo-cylindrical projection. (packages: sp, maptools, rgdal, raster).
 This raster has a global extent, and the cells are .5 degrees each, for
matrix dimensions 360, 720 when still in +latlong.

When I transform the layer and spplot() it, I wind up with new matrix
dimensions (267, 734).  Losing the rows isn't terribly surprising -- the NA
data was removed.  I get that.  But I have no idea where the extra columns
came from.  Furthermore, these extra columns are causing Alaska/the Bering
Straits to appear on our plot twice -- once on the left hand side, and once
on the right hand side.  I've attached an image here:
http://students.washington.edu/jeckert1/should_look_like_this.png -- this
doesn't occur in any other projection than the cylindrical projections.
 Spherical are fine.

I'm guessing that this is caused by attempting to project a
(pseudo)cylindrical projection onto a rectangle.  If I reproject the same
raster in Arc, it truncates the "extra" set of AK/Bering Straits on the
right hand side of the image.  I've attached an image here:
http://students.washington.edu/jeckert1/what_it_looks_like.png

Any suggestions on how to go about doing this?  I'm attaching the relevant
snippets of code below.  Thanks for any help you might provide.

library(maptools) # standard
library(sp) # need for spatial anything
library(RColorBrewer) # easy palettes
library(rgeos) # gpclib alternative
library(rgdal) # GDAL/OGR package interface, handles projections
library(raster) # raster package

# set the working directory
setwd("R:/Project/globalnets/rproject")

# define projection as GCS WGS84
# note "projection" for raster, "proj4string" for vector
projection(cropland) = CRS("+proj=longlat +datum=WGS84 +no_defs")
# read in raster .grd
cropland <-(raster("myRaster.grd"))

# transforming to the superiorly named Eckert IV projection
cropland.eck4 <- projectRaster(cropland, crs ="+proj=eck4")
spplot(cropland.eck4)

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