NcDataReader {startR}

NetCDF file data reader for 'startR'

Description

This is a data reader function for NetCDF files, intended for use as parameter file_data_reader in a Start() call. This function complies with the input/output interface required by Start() defined in the documentation for the parameter 'file_data_reader'.

This function uses the function NcToArray() in the package 'easyNCDF', which in turn uses nc_var_get() in the package 'ncdf4'.

Usage

NcDataReader(
  file_path = NULL,
  file_object = NULL,
  file_selectors = NULL,
  inner_indices = NULL,
  synonims
)

Arguments

file_path

A character string indicating the path to the data file to read. See details in the documentation of the parameter 'file_data_reader' of the function Start(). The default value is NULL.

file_object

An open connection to a NetCDF file, optionally with additional header information. See details in the documentation of the parameter 'file_data_reader' of the function Start(). The default value is NULL.

file_selectors

A named list containing the information of the path of the file to read data from. It is automatically provided by Start(). See details in the documentation of the parameter 'file_data_reader' of the function Start(). The default value is NULL.

inner_indices

A named list of numeric vectors indicating the indices to take from each of the inner dimensions in the requested file. It is automatically provided by Start(). See details in the documentation of the parameter 'file_data_reader' of the function Start(). The default value is NULL.

synonims

A named list indicating the synonims for the dimension names to look for in the requested file, exactly as provided in the parameter 'synonims' in a Start() call. See details in the documentation of the parameter 'file_data_reader' of the function Start().

Value

A multidimensional data array with the named dimensions and indices requested in 'inner_indices', potentially with the attribute 'variables' with additional auxiliary data. See details in the documentation of the parameter 'file_data_reader' of the function Start().

See Also

NcOpener NcDimReader NcCloser NcVarReader

Examples

 data_path <- system.file('extdata', package = 'startR', mustWork = TRUE)
 file_to_open <- file.path(data_path, 'obs/monthly_mean/tos/tos_200011.nc')
 file_selectors <- c(dat = 'dat1', var = 'tos', sdate = '200011')
 first_round_indices <- list(time = 1, latitude = 1:8, longitude = 1:16)
 synonims <- list(dat = 'dat', var = 'var', sdate = 'sdate', time = 'time',
                  latitude = 'latitude', longitude = 'longitude')
 sub_array <- NcDataReader(file_to_open, NULL, file_selectors,
                           first_round_indices, synonims)