[R-sig-Geo] Raster to rasterbrick does not preserve Date/Time

[Miluji Sb]

Thank you, Ben! This works well.

Sincerely,

Milu

On Sun, Nov 4, 2018 at 11:08 PM Ben Tupper <btupper using bigelow.org> wrote:

> Hi,
>
> I'm not sure about reading the datetime stamp directly form the file, but
> you have enough info to convert the z-value which is well described in your
> ncdf.  I'm not familiar with the '%.f' format specifier, but it looks like
> it is a fractional day.  Something like this perhaps will work?
>
> z      <- raster::getZ(rbick)
> z0     <- floor(z)
> zf     <- z - z0
> dt     <- as.POSIXct(as.character(z0), format = "%Y%m%d") + 24*60*60*zf
> rbrick <- raster::setZ(rbrick, z, name = 'datetime')
>
> You'll need to think through the timezone issues that might arise.
> as.POSIXct() has arguments that can help you with that.
>
> Cheers,
> Ben
>
>
> > On Nov 4, 2018, at 12:39 PM, Miluji Sb <milujisb using gmail.com> wrote:
> >
> > Dear all,
> >
> > I have a raster with multiple variables and date/time information;
> >
> >      time  Size:17164   *** is unlimited ***
> >            standard_name: time
> >            bounds: time_bnds
> >            units: day as %Y%m%d.%f
> >            calendar: proleptic_gregorian
> >        bnds  Size:2
> >
> > My goal is to convert the raster file to rasterbrick for extraction
> > purposes;
> >
> > rbrick <- brick(r,  values=TRUE, varname="var1")
> >
> > However, after conversion - the date/time information is not preserved.
> How
> > can I preserve this information?
> >
> > class       : RasterBrick
> > dimensions  : 600, 1440, 864000, 17164  (nrow, ncol, ncell, nlayers)
> > resolution  : 0.25, 0.25  (x, y)
> > extent      : -180, 180, -60, 90  (xmin, xmax, ymin, ymax)
> > coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0
> > data source : /work/ncfile.nc4
> > names       : X19700101.4375, X19700102.4375, X19700103.4375,
> > X19700104.4375, X19700105.4375, X19700106.4375, X19700107.4375,
> > X19700108.4375, X19700109.4375, X19700110.4375, X19700111.4375,
> > X19700112.4375, X19700113.4375, X19700114.4375, X19700115.4375, ...
> > z-value     : 19700101.4375, 20161231.4375 (min, max)
> > varname     : var1
> >
> > Any help will be greatly appreciated!
> >
> > Sincerely,
> >
> > Milu
> >
> >       [[alternative HTML version deleted]]
> >
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>
> Ben Tupper
> Bigelow Laboratory for Ocean Sciences
> 60 Bigelow Drive, P.O. Box 380
> East Boothbay, Maine 04544
> http://www.bigelow.org
>
> Ecological Forecasting: https://eco.bigelow.org/
>
>
>
>
>
>

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