Line chunking implementations for PostGIS

ST_LineChunk.sql

CREATE OR REPLACE FUNCTION ST_LineChunk(geom geometry, max_length float8) RETURNS SETOF geometry AS $$
WITH
  points AS (
    SELECT generate_series(0, CEIL(ST_Length(geom) / max_length)::int)
      / CEIL(ST_Length(geom) / max_length) "end"
  ),
  line_points AS (SELECT LAG("end", 1) OVER (ORDER BY "end") "start", "end" FROM points)
SELECT ST_LineSubstring(geom, "start", "end")
FROM line_points
WHERE "start" IS NOT NULL AND "start" <> 1
$$ LANGUAGE 'sql' IMMUTABLE;

ST_LineChunkMeters.sql

CREATE OR REPLACE FUNCTION ST_LineChunkMeters(geom geometry, max_length float8) RETURNS SETOF geometry AS $$
WITH
  points AS (
    SELECT generate_series(0, CEIL(ST_LengthSpheroid(geom, 'SPHEROID["GRS_1980",6378137,298.257222101]') / max_length)::int)
      / CEIL(ST_LengthSpheroid(geom, 'SPHEROID["GRS_1980",6378137,298.257222101]') / max_length) "end"
  ),
  line_points AS (SELECT LAG("end", 1) OVER (ORDER BY "end") "start", "end" FROM points)
SELECT ST_LineSubstring(geom, "start", "end")
FROM line_points
WHERE "start" IS NOT NULL AND "start" <> 1
$$ LANGUAGE 'sql' IMMUTABLE;