On Thu, Nov 11, 2010 at 10:20 PM, Jonathan Greenberg <greenb...@ucdavis.edu> wrote: > Folks: > > Robert has a version of this email concerning the implementation in > raster, but I'm wondering if there's something going on with rgdal or > proj? Can anyone think of a reason why reprojecting a file of North > America with the following projection info: > > "+proj=lcc +lat_1=50 +lat_2=50 +lat_0=50 +lon_0=-107 +x_0=5632642 > +y_0=4612546 +ellps=WGS84" > > to > > "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0" > > would be losing all data north of latitude = 46.63769 (even if there > is clearly data above this latitude)? Here's the raster info of the > file I'm trying to reproject: > >> unsynced > class : RasterLayer > filename : > nrow : 277 > ncol : 349 > ncell : 96673 > min value : 0 > max value : 10.1305 > projection : +proj=lcc +lat_1=50 +lat_2=50 +lat_0=50 +lon_0=-107 > +x_0=5632642 +y_0=4612546 +ellps=WGS84 > xmin : -16231.49 > xmax : 11313351 > ymin : -16231.5 > ymax : 8976020 > xres : 32462.99 > yres : 32463 > > A reprojection works in the sense that all data south of latitude = > 46.63769 is placed in the right location. Thoughts? If there isn't > any obvious answer from this non-code post, I'll append some code > based on a new R package I've been developing so the specific datasets > can be examined more closely.
What do you mean by the raster losing data north of 46.6379 degrees? And what are you using to reproject? (Because a raster normally needs transforming to a new grid in the new CRS, spTransform wont do it). I see no problems doing an spTransform on a set of points in the range of your raster summary: pts=data.frame(x=seq(-16231.49,11313351,len=30),y=seq(-16231.5,8976020,len=30),z=1:30) coordinates(pts)=~x+y proj4string(pts)="+proj=lcc +lat_1=50 +lat_2=50 +lat_0=50 +lon_0=-107 +x_0=5632642 +y_0=4612546 +ellps=WGS84" spTransform(pts,CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0")) gives me 30 points with no NA's or anything unexpected... Barry _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo