Find schemas associated with a particular user

Select schemas in current db associated with user myuser, even if there are no tables in the schema, including public schema:

select 'public' as nspname
 union all
select nspname
  from pg_catalog.pg_namespace as nsp
  join pg_catalog.pg_roles as rls
    on nsp.nspowner = rls.oid
 where rls.rolname = 'myuser';