Hi list,

I need to process a tiled raster data set as a continuous raster. However
it's too large to fit in memory (14G cells) and writing it as a single file
isn't very efficient (many tiles are completely NA, because the shape isn't
regular).
To avoid edge effect when processing, I need to compute each tile with a
buffer around it and crop it at the end of the operation. I was wondering
what functions/packages could be helpful or if there is one already allowing
the usage of tiles for raster operations.
Here's my solution for the moment:

# build a gdal vrt file
system("buildgdalvrt cover.vrt *.tif")
r <- raster("cover.vrt")
# list all rasters extents
l <- lapply(list.files("E:/geodata/brut/TIF_MHC/", patt="*.tif", full=TRUE),
raster)
ext <- lapply(l, extent)
# buffer the extents (tbd)
# use buffered extents to crop the vrt
# e.g. (no buffer applied):
tile <- crop(r, ext[[1]])
# Error : Failure during raster IO

Any idea would be much appreciated.

Thanks,
Etienne

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