Expand description
Multi-Ordered healpix Map (MOM)
Here we assume that a MOM a simply a set of of (key, value)
pairs in which:
- the
key
is a UNIQ NESTED HEALPix cell number - all the
keys
in the set are non-overlapping - we assume nothing on the
key
ordering - the
value
(e.g. a probability) is proportional to the cell area, i.e. we can split a(key, value)
at the order N+1 into the 4(key, value)
pairs:(key << 2 + 0, value / 4)
(key << 2 + 1, value / 4)
(key << 2 + 2, value / 4)
(key << 2 + 3, value / 4)