select * from (
select
schemas.nspname
from
(
    select
    nspname,
    nspowner
    from pg_namespace
) schemas,
(
    SELECT usesysid FROM pg_user WHERE usename = 'postgres'
) owner
where
schemas.nspowner = owner.usesysid
union
/*granted schemas*/
select
s.nspname
from
(
select
nspname,
cast(unnest(nspacl) as name) membership
from pg_namespace
) s,
(
    select
    *
    from
    (
        select
        groname,
        unnest(grolist) usesysid
        from
        pg_group
    ) groups
    join
    (
        SELECT usesysid FROM pg_user WHERE usename = 'postgres'
    ) users on
    groups.usesysid = users.usesysid
) roles
where
strpos(s.membership, roles.groname) > 0
union
/* no nspacl defined => access to public */
select
nspname
from pg_namespace
where
nspacl is null
union
/* public defined explicitly */
select
nspname
from
(
    select
    nspname,
    cast(unnest(nspacl) as name) membership
    from pg_namespace
) schemas
where
substring(schemas.membership, 1, 1) = '='
) As sc
where sc.nspname !~ '^pg_temp' And sc.nspname !~ '^pg_toast'