How to create a Trajectory

A raw Trajectory can be created by adding constituents, which can be other trajectories, measurements, vertices, etc. The simplest case is when the trajectory is made of measurements:

Trajectory traj;
traj.add_constituent(meas1);
traj.add_constituent(meas2);
traj.add_constituent(meas3);

where the Measurements has being created previously . This trajectory can be now fitted.