描述

测试两个移动物体是否曾经比指定距离更近。

输入必须是经 ST_IsValidTrajectory 检查的有效轨迹。 如果轨迹在其 M 范围内不重叠，则返回 False。

可用性：2.2.0

该函数支持 3d 并且不会丢失 z-index。

示例

WITH inp AS ( SELECT
  ST_AddMeasure('LINESTRING Z (0 0 0, 10 0 5)'::geometry,
    extract(epoch from timestamp '2015-05-26 10:00' AT TIME ZONE 'UTC'),
    extract(epoch from timestamp '2015-05-26 11:00' AT TIME ZONE 'UTC')
  ) a,
  ST_AddMeasure('LINESTRING Z (0 2 10, 12 1 2)'::geometry,
    extract(epoch from timestamp '2015-05-26 10:00' AT TIME ZONE 'UTC'),
    extract(epoch from timestamp '2015-05-26 11:00' AT TIME ZONE 'UTC')
  ) b
)
SELECT ST_CPAWithin(a,b,2), ST_DistanceCPA(a,b) distance FROM inp;

st_cpawithin |     distance
--------------+------------------
 t            | 1.9652147377620688

相关信息

ST_IsValidTrajectory, ST_ClosestPointOfApproach, ST_DistanceCPA, |=|