Returns the velocity of a trajectory at a specified point in time.
Syntax
float8 ST_VelocityAtTime (trajectory traj, timestamp t);Parameters
| Parameter | Type | Description |
|---|---|---|
traj |
trajectory | The trajectory object. |
t |
timestamp | The time point at which to retrieve the velocity. |
Return value
Returns a float8 value representing the velocity recorded in the trajectory's velocity attribute field at time t.
Example
Select ST_velocityAtTime(traj, '2010-1-11 23:40:00') From traj_table;该文章对您有帮助吗？