makeSubset: Reads an arbitrary data slice
In SantanderMetGroup/loadeR: A climate4R package for data access <http://meteo.unican.es/climate4r>

makeSubset

R Documentation

Reads an arbitrary data slice

Description

Reads an arbitrary data slice from a new GeoGrid that is a logical subset of the original GeoGrid.

Usage

makeSubset(grid, timePars, levelPars, latLon, memberPars)

Arguments

`grid`	A grid of the java class ‘ucar.nc2.dt.grid.GeoGrid’
`timePars`	A list of time parameters as returnde by `getTimeDomain`.
`levelPars`	Vertical level parameters, as returned by `getVerticalLevelPars`. The element `zRange` is a ‘ucar.ma2.Range’ or a null reference.
`latLon`	A list of geospatial parameters, as returned by `getLatLonDomain`.

Value

A n-dimensional array with the selected subset data.

Note

The process is somewhat tricky because R cannot adequately represent NDjavaArrays. Several tests have shown that R (unlike MatLab) puts zeroes where they shouldn't be when using the ‘copyToNDjavaArray’ method. Hence, the data returned from ‘readDataSlice’ are converted to a 1D array (‘copyTo1DjavaArray’ method), and then put back in a n-dimensional R array. This is achieved by reversing the GeoGrid dimension ordering. In addition, the particular case of single-coordinate selections (either in X and/or in Y dimensions) must be adequately handled given that the ‘makeSubset’ output has in this case a different shape than the final output after “slicing”.