GeoMesa's index uses a shard id as the beginning of the key to allow for horizontal scalability. It encodes spatio-temporal data in Accumulo keys using space filling curves. Queries are applied in parallel at scan time through stacked server side iterators to implement (E)CQL standard queries.

6. How Does GeoMesa’s Index Work?
Constructs a key beginning with a
shard id for horizontal scalability.
Uses Space Filling Curves to encode
spatio-temporal data in Accumulo
keys.
Stacks server side iterators to apply
(E)CQL standard queries in parallel
at scan time.