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

[Lyndon Estes]

Based on the example by Pierre:

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

> show(r)
class       : RasterLayer
dimensions  : 77, 101, 7777  (nrow, ncol, ncell)
resolution  : 1, 1  (x, y)
extent      : 0, 101, 0, 77  (xmin, xmax, ymin, ymax)
projection  : +proj=merc +ellps=WGS84
values      : none

# Set to NA
r[] <- NA
> show(r)
class       : RasterLayer
dimensions  : 77, 101, 7777  (nrow, ncol, ncell)
resolution  : 1, 1  (x, y)
extent      : 0, 101, 0, 77  (xmin, xmax, ymin, ymax)
projection  : +proj=merc +ellps=WGS84
values      : in memory
min value   : NA
max value   : NA

So this should work for your raster:

D10N2009[] <- NA


Cheers, Lyndon


On Wed, May 25, 2011 at 2:32 AM, Roman Luštrik <roman.lustrik at gmail.com> wrote:
> I would use setValues on individual layer.
>
> Cheers,
> Roman
>
>
>
> On Wed, May 25, 2011 at 8:25 AM, Pierre Roudier <pierre.roudier at gmail.com>wrote:
>
>> 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
>> >
>> > _______________________________________________
>> > R-sig-Geo mailing list
>> > R-sig-Geo at r-project.org
>> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>> >
>>
>>
>>
>> --
>> Scientist
>> Landcare Research, New Zealand
>>
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>> R-sig-Geo at r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>
>
>
> --
> In God we trust, all others bring data.
>
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-- 
Lyndon Estes
Research Associate
Woodrow Wilson School
Princeton University
+1-609-258-2392 (o)
+1-609-258-6082 (f)
+1-202-431-0496 (m)
lestes at princeton.edu