Transforms a trajectory from one spatial reference system to another by recalculating the coordinates to match the target system — not just updating the spatial reference identifier (SRID) label.
Syntax
trajectory ST_Transform(trajectory traj, int srid)Parameters
| Parameter | Description |
|---|---|
traj | The trajectory to transform. The trajectory can be transformed to the specified spatial reference only when the trajectory has an SRID. |
srid | The SRID of the target spatial reference system. |
Example
The following example converts a trajectory from SRID=4326 to SRID=2401.
SELECT ST_Transform(
'{"trajectory":{"version":1,"type":"STPOINT","leafcount":4,"start_time":"2020-11-03 08:00:00","end_time":"2020-11-03 18:03:20","spatial":"SRID=4326;LINESTRING(114.49211 37.97999,114.49211 37.97521,114.49191 37.98021,124 37)","timeline":["2020-11-03 08:00:00","2020-11-03 08:01:40","2020-11-03 08:03:20","2020-11-03 18:03:20"]}}'::trajectory,
2401
);Output:
{"trajectory":{"version":1,"type":"STPOINT","leafcount":4,"start_time":"2020-11-03 08:00:00","end_time":"2020-11-03 18:03:20","spatial":"SRID=2401;LINESTRING(29019418.8397 5025539.47515,29019696.5878 5024992.53808,29019387.9428 5025555.44863,29954166.377 5430882.06455)","timeline":["2020-11-03 08:00:00","2020-11-03 08:01:40","2020-11-03 08:03:20","2020-11-03 18:03:20"]}}The spatial field changes from the coordinates of SRID 4326 to the coordinates of SRID 2401. All other fields — version, type, leafcount, start_time, end_time, and timeline — remain unchanged.
Usage notes
The source trajectory must have an SRID. The trajectory can be transformed to the specified spatial reference only when the trajectory has an SRID.