def create_index(data, leafsize=10):
"""
Creates the k-D tree index.
:param data: list of HyperPoints to index
"""
spatial_points = data[['latitude', 'longitude']]
if hasattr(data, 'data'):
mask = np.ma.getmask(data.data).ravel()
else:
mask = None
return HaversineDistanceKDTree(spatial_points,
mask=mask,
leafsize=leafsize)
