ST_Intersects Trajectory Intersection Functions Overview - PolarDB

Checks whether two spatial objects share at least one point in the specified dimension(s). Returns true if they intersect; returns false otherwise.

Syntax

bool ST_{2D|3D}Intersects(geometry geom, trajectory traj);
bool ST_{2D|3D}Intersects(trajectory traj, geometry geom);
bool ST_{2D|3D}Intersects(geometry geom, trajectory traj, timestamp ts, timestamp te);
bool ST_{2D|3D}Intersects(trajectory traj, geometry geom, timestamp ts, timestamp te);
bool ST_{Z|T|2D|2DT|3D|3DT}Intersects(boxndf box, trajectory traj);
bool ST_{Z|T|2D|2DT|3D|3DT}Intersects(trajectory traj, boxndf box);
bool ST_{Z|T|2D|2DT|3D|3DT}Intersects(boxndf box, trajectory traj, timestamp ts, timestamp te);
bool ST_{Z|T|2D|2DT|3D|3DT}Intersects(trajectory traj, boxndf box, timestamp ts, timestamp te);
bool ST_{2D|2DT|3D|3DT}Intersects(trajectory traj1, trajectory traj2);
bool ST_{2D|2DT|3D|3DT}Intersects(trajectory traj1, trajectory traj2, timestamp ts, timestamp te);

Parameters

Parameter	Type	Description
`geom`	geometry	The geometry to compare.
`traj`	trajectory	The trajectory to compare, or the original trajectory that contains the sub-trajectory to compare.
`traj1`	trajectory	The trajectory to compare, or the original trajectory that contains the sub-trajectory to compare.
`traj2`	trajectory	The trajectory to compare, or the original trajectory that contains the sub-trajectory to compare.
`box`	boxndf	The bounding box to compare.
`ts`	timestamp	The start of the time range used to extract a sub-trajectory. Optional.
`te`	timestamp	The end of the time range used to extract a sub-trajectory. Optional.

Description

The function suffix controls which dimensions the intersection check covers:

Suffix	Dimensions checked
`2D`	X and Y axes
`3D`	X, Y, and Z axes
`T`	Time dimension only
`Z`	Z axis only
`2DT`	X, Y, and time
`3DT`	X, Y, Z, and time

For any dimension not covered by the suffix, the function treats that dimension as unconstrained — any value qualifies.

Complete trajectories vs. sub-trajectories:

Without ts and te: compares the full trajectories of both objects.
With ts and te: extracts sub-trajectories over the specified time range, then compares those sub-trajectories.

`ST_Intersects` alias behavior:

ST_Intersects(...) is equivalent to:

ST_2DIntersects(...) when one of the objects is a geometry
ST_3DTIntersects(...) when both objects are trajectories

Example

The following example checks four intersection variants between two trajectories: ST_2dIntersects, ST_2dtIntersects, ST_3dIntersects, and ST_3dtIntersects. The two trajectories share spatial extent in 2D and 3D but have non-overlapping time ranges, so only the spatial-only checks return t.

WITH traj AS (
    SELECT (
        '{"trajectory":{"version":1,"type":"STPOINT","leafcount":6,"start_time":"2000-01-01 03:15:42","end_time":"2000-01-01 05:16:43",' ||
        '"spatial":"LINESTRING(2 2 0,33.042158099636 36.832684322819 0,47.244002354518 47.230026333034 0,64.978971942887 60.618813472986 0,77.621717839502 78.012496630661 0,80 78 0)",' ||
        '"timeline":["2000-01-01 03:15:42","2000-01-01 03:39:54","2000-01-01 04:04:06","2000-01-01 04:28:18","2000-01-01 04:52:31","2000-01-01 05:16:43"]}}'
    )::trajectory a,
    (
        '{"trajectory":{"version":1,"type":"STPOINT","leafcount":4,"start_time":"2000-01-01 02:17:58.656079","end_time":"2000-01-01 03:43:59.620923",' ||
        '"spatial":"LINESTRING(40 2 0,15.17549143297 51.766017656152 0,1.444002354518 69.630026333034 0,3 70 0)",' ||
        '"timeline":["2000-01-01 02:17:58.656079","2000-01-01 02:46:38.977693","2000-01-01 03:15:19.299307","2000-01-01 03:43:59.620923"]}}'
    )::trajectory b
)
SELECT ST_2dIntersects(a, b), ST_2dtIntersects(a, b), ST_3dIntersects(a, b), ST_3dtIntersects(a, b)
FROM traj;

Output:

 st_2dintersects | st_2dtintersects | st_3dintersects | st_3dtintersects
-----------------+------------------+-----------------+------------------
 t               | f                | t               | f