read.nc {RNetCDF}

Read a NetCDF Dataset

Description

Read all data from a NetCDF dataset.

Usage

   read.nc(ncfile, recursive=FALSE, ...)

Arguments

ncfile

Object of class NetCDF which points to the NetCDF dataset (as returned from open.nc).

recursive

Descend recursively into any groups in the dataset if TRUE.

...

Optional arguments passed to var.get.nc.

Details

This function reads all variable data from a NetCDF dataset into a list. The list elements (arrays) have the same names as the variables in the NetCDF dataset.

Groups in the dataset may optionally be read recursively and returned as nested lists. Each list has the name of the corresponding group in the dataset.

Value

A list with the list elements containing an array for each variable or a (possibly nested) list for each group in the NetCDF dataset.

Author(s)

Pavel Michna, Milton Woods

References

https://www.unidata.ucar.edu/software/netcdf/

Examples

##  Create a new NetCDF dataset
file1 <- tempfile("read_", fileext=".nc")
nc <- create.nc(file1, format="netcdf4")

dim.def.nc(nc, "station", 5)
dim.def.nc(nc, "time", unlim=TRUE)
dim.def.nc(nc, "max_string_length", 32)

##  Create two coordinate variables
var.def.nc(nc, "time", "NC_INT", "time")
var.def.nc(nc, "name", "NC_CHAR", c("max_string_length", "station"))

## Create a group to contain the data
# This is not necessary, but shows it can be done.
grp <- grp.def.nc(nc, "data")

## Create a data variable
var.def.nc(grp, "temperature", "NC_DOUBLE", c("station","time"))

##  Put some _FillValue attribute for temperature
att.put.nc(grp, "temperature", "_FillValue", "NC_DOUBLE", -99999.9)

##  Define variable values
mytime        <- c(1:2)
mytemperature <- c(1.1, 2.2, 3.3, 4.4, 5.5, 6.6, 7.7, NA, NA, 9.9)
myname        <- c("alfa", "bravo", "charlie", "delta", "echo")

##  Put the data
var.put.nc(nc, "time", mytime, 1, length(mytime))
var.put.nc(nc, "name", myname, c(1,1), c(32,5))
var.put.nc(grp, "temperature", mytemperature, c(1,1), c(5,2))

sync.nc(nc)

##  Read the dataset, including the contents of any groups
read.nc(nc, recursive=TRUE)

close.nc(nc)
unlink(file1)