Return the time-weighted centroid

twCentroid(tnpoint) → geometry(Point)

SELECT ST_AsText(twCentroid(tnpoint '{[NPoint(1, 0.3)@2001-01-01,
  NPoint(1, 0.5)@2001-01-02, NPoint(1, 0.5)@2001-01-03, NPoint(1, 0.7)@2001-01-04)}'));
-- POINT(79.9787466444847 46.2385558051041)