Rectangle splitter for Postgis

rectangle_equal_splitter.sql

-- blades part adapted from "https://gis.stackexchange.com/questions/104439/how-to-extend-a-straight-line-in-postgis"
with medialaxis_multi as(
    select
    	polygons.id,
        st_union(ST_ApproximateMedialAxis(geom)) as geom
    from
        polygons
    group by 
    	polygons.id
),
medialaxis_single as(
    select
    	id,
        (st_dump(geom)).geom as geom
    from
        medialaxis_multi
),
blades as (
    select 
        id, 
        st_makeline(st_translate(a, sin(az1) * len, cos(az1) * len),st_translate(b,sin(az2) * len, cos(az2) * len)) as geom
    from (
            select 
                id,
                a,
                b, 
                st_azimuth(a,b) as az1, st_azimuth(b, a) as az2, st_distance(a,b) + 1 as len
            from (
                select 
                    id,
                    st_startpoint(geom) as a, 
                    st_endpoint(geom) as b
                from 
                    medialaxis_single
            )   as sub
        )   as sub2
)
select 
	blades.id,
    (st_dump(st_split(polygons.geom,blades.geom))).geom
from    
    polygons,
    blades
where
	polygons.id = blades.id
  ;