描述

返回兩個軌跡在其最近接近點的距離 (以 2D 計算)。

輸入必須是有效的軌跡，由 ST_IsValidTrajectory 檢查。如果軌跡的 M 值範圍沒有重疊，則返回 Null。

可用性：2.2.0

此函數支援 3D，且不會捨棄 z 索引。

範例

-- Return the minimum distance of two objects moving between 10:00 and 11:00
WITH inp AS ( SELECT
  ST_AddMeasure('LINESTRING Z (0 0 0, 10 0 5)'::geometry,
    extract(epoch from '2015-05-26 10:00'::timestamptz),
    extract(epoch from '2015-05-26 11:00'::timestamptz)
  ) a,
  ST_AddMeasure('LINESTRING Z (0 2 10, 12 1 2)'::geometry,
    extract(epoch from '2015-05-26 10:00'::timestamptz),
    extract(epoch from '2015-05-26 11:00'::timestamptz)
  ) b
)
SELECT ST_DistanceCPA(a,b) distance FROM inp;

     distance
------------------
 1.96036833151395

另請參閱

ST_IsValidTrajectory、ST_ClosestPointOfApproach、ST_AddMeasure、|=|