Package v2grid

Variant 2 grids. Extract from the compressed RDNAPTRANS(tm)2018_v229627 naptrans2018.txt.zip and rdtrans2018.txt.zip grid files only columns NAP_..., lat_corr_ and lon_corr_ and encode each as a row-order matrix in Python, a 481-tuple of 301-arrays of single- or double precision floats.