Add variables to an existing netCDF file in R

Question

I have a netCDF file with one variable 'gpwcount' and its lat/lot coordinates also available. The dimension of this 'gpwcount' variable is 1050 rows x 1050 columns. This file consists of population count data for the year 2015 from three west African countries that had a major Ebola outbreak. The file is attached here

I am trying to model an epidemic and run a simulation. Is there a way to add the following variables to the existing netCDF file using R (or any other tool).

The variables I would like to add are labelled,

 Exposed (1050 x 1050 grid all filled with 0);
 Infected (1050 x 1050 grid all filled with 0);
 Hospitalised (1050 x 1050 grid all filled with 0);
 Recovered (1050 x 1050 grid all filled with 0);
 Dead (1050 x 1050 grid all filled with 0);
 Prevalence (1050 x 1050 grid all filled with 0);
 Inhabitable (1050 x 1050 grid all filled with either 0 if the gpwcount in that cell is 0 or a 1 if gpwcount in that cell is greater than 0);

Answer 1

You can use the function addLayer() from package raster.

Example:

## read your file
ras_netcdf <- raster(".../episim_Africacount_0000.nc")

## let's create a similar raster, fill it with zero
ras_empty <- ras_netcdf
ras_empty[1:ncell(ras_empty)] <- 0
names(ras_empty) <- "Exposed"

# add the layer
ras_netcdf2 <- addLayer(ras_netcdf, ras_empty)

NOTE: you could also use the function ncvar_add from package ncdf4