Thanks, I basically have to reclass() all 72 tiles, then aggregate() them from 30 arc seconds to 5 minutes and eventually put them in a brick with other rasters so I can average across the layers.
I thought unionExtent() was going to be the ticket, but that just effects the extent. unionRaster() is really what would be cool for working with tiles. I'll take a look at the gdal stuff Steve On Sun, Oct 16, 2011 at 10:01 PM, Robert J. Hijmans <r.hijm...@gmail.com> wrote: > Steven, > In principle you could give merge all tiles (e.g. make a list of RasterLayer > objects and use do.call ) but merge is quite slow (something that can easily > be be improved; and I expect it will be over the coming months). > What I would do is use run gdalbuildvrt (that comes with the FWtools). This > creates a single header file that lets you access all the tiles as a single > virtual file. If you want a single file for better performance, you can use > writeRaster to save it to e.g. a single geotiff file. > > Robert > > On Sun, Oct 16, 2011 at 8:54 PM, steven mosher <mosherste...@gmail.com> > wrote: >> >> I have 72 "tiles" in a tif format and each tile is 30X30 >> >> >tile >> class : RasterLayer >> dimensions : 3600, 3600, 12960000 (nrow, ncol, ncell) >> resolution : 0.008333333, 0.008333333 (x, y) >> extent : 60, 90, 60, 90 (xmin, xmax, ymin, ymax) >> coord. ref. : NA >> values : C:/Users/steve/.... >> min value : 0 >> max value : 255 >> >> What I'd like to do is find the fastest way to bring all 72 tiles >> into one big raster. >> >> merge() seems like one good choice, where I would merge each tile >> with a blank raster that would get >> filled in incrementally by each tile >> >> > world >> class : RasterLayer >> dimensions : 21600, 43200, 933120000 (nrow, ncol, ncell) >> resolution : 0.008333333, 0.008333333 (x, y) >> extent : -180, 180, -90, 90 (xmin, xmax, ymin, ymax) >> coord. ref. : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs >> +towgs84=0,0,0 >> values : none >> >> world <- merge(tile, world) >> >> and the repeat that for the remaining 71 tiles. I'm also think that >> one could extract the values from the tile >> and use setValues but that appears to hit the memory wall in >> Windows. The other option >> I suppose is to use writeValues() and create a big file from the tiles. >> >> Am I missing any obvious options? >> >> Steve >> >> _______________________________________________ >> 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