PostGIS
Name
ST_DistanceCPA — Returns the distance between the closest point of approach of two trajectories.
Description
Returns the minimum distance two moving objects have ever been each other.
Inputs must be valid trajectories as checked by ST_IsValidTrajectory. Null is returned if the trajectories do not overlap in their M ranges.
Availability: 2.2.0
This
function supports 3d and will not drop the z-index.
Examples
-- 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