[R-sig-Geo] writeRaster does not preserve names when writing to NetCDF

[Barry Rowlingson]

This chunk of code writes a character vector to a file.  It needs two
dimensions, one that has to be big enough for the longest character
string, and one which has to be the length of the vector.

writeChars <- function(fn){
    nameDim = dim.def.ncdf("NamesDim","", 1:3)
    charDim = dim.def.ncdf("CharsDim","", 1:10)
    nameVar = var.def.ncdf("Names","",list(charDim,nameDim),"NA")
    nc = create.ncdf(fn, list(nameVar))
    v = c("red  ","green","blue ")
    for(i in 1:length(v)){
        put.var.ncdf(nc, nameVar, v[i], start=c(1,i), count=c(-1,1))
    }
    close.ncdf(nc)
}

Dumping the NetCDF gives:

data:
 CharsDim = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ;
 NamesDim = 1, 2, 3 ;
 Names =
  "red  ",
  "green",
  "blue " ;
}

Whether this is a good idea or not... Hmmmm....

I've noticed if you use `writeRaster` with format="CDF" you get the
data in one variable called "value", but if you use format="netCDF"
you get one named variable for each layer. I'm pretty sure these names
could be set and recovered, but currently they seem to be called Band1
etc. I think thats the GDAL driver at work:

"""
   This driver supports creation of netCDF file following the CF-1
convention. You may create set of 2D
   datasets. Each variable array is named Band1, Band2, ... BandN.
""" http://www.gdal.org/frmt_netcdf.html

Also, this section in writeRaster:

          NetCDF files have the following additional, optional,
          arguments: ‘varname’, ‘varunit’, ‘longname’, ‘xname’,
          ‘yname’, ‘zname’, ‘zunit’

only seems to apply to format="CDF" and not "NetCDF", which seems to
ignore at least the ones I've tried. The "NetCDF" format seems to be
done via GDAL.

Is it worth putting any effort into this? I mean, is it worth *Robert*
putting any effort into this?

Barry