Data arrays of shape=(nsweeps, nrays, nbins) for each data type.
Indexed by data type name (str).
metadata : dict of dicts
Arrays of ‘azimuth_0’, ‘azimuth_1’, ‘elevation_0’, ‘elevation_1’,
‘nbins’, and ‘time’ for each data type. Indexed by data type name
(str). Rays which were not collected are marked with a value of
-1 in the ‘nbins’ array.