Conteo temporal

tCount(tcbuffer) → {tintSeq,tintSeqSet}

WITH Temp(temp) AS (
  SELECT tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01,
    Cbuffer(Point(1 1), 0.3)@2001-01-03)' UNION
  SELECT tcbuffer '[Cbuffer(Point(1 1), 0.2)@2001-01-02,
    Cbuffer(Point(1 1), 0.4)@2001-01-04)' UNION
  SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-03,
    Cbuffer(Point(1 1), 0.5)@2001-01-05)' )
SELECT tCount(Temp)
FROM Temp;
-- {[1@2001-01-01, 2@2001-01-02, 1@2001-01-04, 1@2001-01-05)}

Conteo de ventana

wCount(tcbuffer) → {tintSeq,tintSeqSet}

WITH Temp(temp) AS (
  SELECT tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01,
    Cbuffer(Point(1 1), 0.3)@2001-01-03)' UNION
  SELECT tcbuffer '[Cbuffer(Point(1 1), 0.2)@2001-01-02,
    Cbuffer(Point(1 1), 0.4)@2001-01-04)' UNION
  SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-03,
    Cbuffer(Point(1 1), 0.5)@2001-01-05)' )
SELECT wCount(Temp, '1 day')
FROM Temp;
/* {[1@2001-01-01, 2@2001-01-02, 3@2001-01-03, 2@2001-01-04, 1@2001-01-05,
   1@2001-01-06)} */

Agregar los centros de un conjunto de búferes circulares temporales en su centroide temporal, convirtiendo a tgeompoint

tCentroid(tcbuffer::tgeompoint) → tgeompoint

La agregación pertenece al tipo tgeompoint: la trayectoria del centro de un búfer circular es un punto temporal, de modo que la conversión alcanza la agregación en lugar de que el tipo búfer lleve su propia copia.

WITH Temp(temp) AS (
  SELECT tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01,
    Cbuffer(Point(1 1), 0.3)@2001-01-03)' UNION
  SELECT tcbuffer '[Cbuffer(Point(3 3), 0.2)@2001-01-01,
    Cbuffer(Point(3 3), 0.4)@2001-01-03)' )
SELECT asText(tCentroid(temp::tgeompoint)) FROM Temp;
-- {[POINT(2 2)@2001-01-01, POINT(2 2)@2001-01-03)}