[R-sig-Geo] raster: creating a layer of NA

[Pierre Roudier]

Hi Agustin,

What about this:

# Create a Raster object
logo <- raster(system.file("external/rlogo.grd", package="raster"))
# Use this rastre to create a new, void Raster object
r <- raster(logo)
show(r)

Pierre

2011/5/25 Agustin Lobo <alobolistas at gmail.com>:
> HI!
>
> I must create a layer with all missing values. I try:
>> show(D10N2009)
> class       : RasterBrick
> dimensions  : 393, 606, 35  (nrow, ncol, nlayers)
> resolution  : 0.008928571, 0.008928571  (x, y)
> extent      : -2.004464, 3.40625, 40.49554, 44.00446  (xmin, xmax, ymin, ymax)
> projection  : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0
> values      : /media/Iomega_HDD/FLUXPYR/VGTFLUXPYR1/D10/FLXP_NDD10_2009.vrt
> min values  : 0 0 0 0 0 0 0 0 0 0 ...
> max values  : 255 255 255 255 255 255 255 255 255 255 ...
>
>> delme = D10N2009[[1]]*0
>> show(delme)
> class       : RasterLayer
> dimensions  : 393, 606, 238158  (nrow, ncol, ncell)
> resolution  : 0.008928571, 0.008928571  (x, y)
> extent      : -2.004464, 3.40625, 40.49554, 44.00446  (xmin, xmax, ymin, ymax)
> projection  : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0
> values      : in memory
> min value   : 0
> max value   : 0
>
> But
>> delme = D10N2009[[1]]*NA
> Error in D10N2009[[1]] * NA : non-numeric argument to binary operator
>
> I also try
>> NAvalue(delme) <- 0
> but no trace of the NAs:
>> show(delme)
> class       : RasterLayer
> dimensions  : 393, 606, 238158  (nrow, ncol, ncell)
> resolution  : 0.008928571, 0.008928571  (x, y)
> extent      : -2.004464, 3.40625, 40.49554, 44.00446  (xmin, xmax, ymin, ymax)
> projection  : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0
> values      : in memory
> min value   : 0
> max value   : 0
>
> By now I write with NAflag=0 and read back, but there must be a
> cleaner way of generating a layer with all NA values
> (it's a missing layer for a particular time)
>
> Thanks!
>
> Agus
>
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-- 
Scientist
Landcare Research, New Zealand