tc

flatearth-tc

/* https://twitter.com/tkardi/status/1521366132371902465 */

drop table if exists tc;
create table tc as 
select gid, path, 
    st_lineinterpolatepoint(
        st_scale(
            st_rotate(
                st_exteriorring(
                    st_buffer(
                        st_setsrid(st_point(0,0),4326)::geography,
                        st_distance(st_setsrid(st_point(0,90),4326)::geography, geom::geography) / pi()
                    )::geometry(polygon, 4326)
                ),
                radians(90)
            ), 1.70, 1.70 --3, 1.5 /* don't distort here, let mercator do it instead ! */
        ),
        st_azimuth(st_setsrid(st_point(0, 90),4326)::geography,geom::geography) / (2*pi())
    ) as geom
from (
    select gid, (st_dumppoints(geom)).*  
    from ne_10m_admin_0_countries 
) f
where st_y(geom) >-85 
--and gid = 176 /* antarctica */
;

/* outer bounds for antarctica, gid = 176*/
insert into tc (
    gid, path, geom
)
select 
    gid, array[0, path[2], path[3]] as path, geom
from (
    select 
        176 as gid, 
        (st_dumppoints(st_multi(st_envelope(st_makeline(array[st_setsrid(st_point(-180,-85),4326),st_setsrid(st_point(180,85),4326)]))))).*
) g
;

alter table tc add column oid serial;
alter table tc add constraint pk__tc primary key (oid);
create index sidx__tc on tc using gist (geom);

drop table if exists tc_area;
create table tc_area as
select 
    gid, (st_dump(st_buildarea(st_node(st_collect(l))))).geom as geom
from (
    select 
        gid, path[1] as part, path[2] as ring, 
        st_makeline(array_agg(geom order by path[3])) as l
    from tc 
    group by 
        gid, path[1], path[2]
) g
group by gid;

alter table tc_area add column oid serial;
alter table tc_area add constraint pk__tc_area primary key (oid);
create index sidx__tc_area on tc_area using gist (geom);

drop table if exists tc_area_continents;
create table tc_area_continents as
select (st_dump(st_union(geom))).geom
from tc_area;

gistfile1.txt

/* https://twitter.com/tkardi/status/1520405854180503554 */

drop table if exists tc;
create table tc as 
select row_number() over()::int as oid, gid, path, 
    st_project(
        st_setsrid(st_point(-30,0),4326)::geography,
        st_distance(st_setsrid(st_point(0,90),4326)::geography, geom::geography),
        st_azimuth(st_setsrid(st_point(0,90),4326)::geography,geom::geography) - radians(125)
    )::geometry(point, 4326) as geom
from (
    select gid, (st_dumppoints(geom)).*  
    from ne_10m_admin_0_countries ) f
where st_y(geom) >-88
;

alter table tc add constraint pk__tc primary key (oid);
create index sidx__tc on tc using gist (geom);

--select * from tc limit 10

drop table if exists tc_area;
create table tc_area as
select 
    gid, (st_dump(st_buildarea(st_node(st_collect(l))))).geom as geom
from (
    select 
        gid, path[1] as part, path[2] as ring, 
        st_makeline(array_agg(geom order by path[3])) as l
    from tc 
    group by 
        gid, path[1], path[2]
) g
group by gid;

alter table tc_area add column oid serial;
alter table tc_area add constraint pk__tc_area primary key (oid);
create index sidx__tc_area on tc_area using gist (geom);

drop table if exists tc_area_continents;
create table tc_area_continents as
select (st_dump(st_union(geom))).geom
from tc_area;