Trajectory actor, together with a transfer function.

Description

The trajectory actor draws Lagrangian particle trajectories (path lines) or streamlines into a scene, either as 3D tubes or as particle positions.

• Selected features:
  • Supports 3-D visual analysis of pre-computed particle trajectories or particle-clouds.
  • A converter is available for LAGRANTO trajectories. Also, converters for some of the output of the atmospheric dispersion models HYSPLIT and NAME are available (please contact us).
  • Trajectories can be drawn as 3D tubes, coloured by pressure elevation and (new in Met.3D 1.7) any other variable that is provided as auxiliary input data or has been traced/sampled along trajectories computed in Met3D.
  • Shadows of the trajectories may be rendered to the surface.
  • The individual positions of the trajectory particles can also be drawn, either for the entire trajectories or for individual time steps.
  • Animations of particle positions are possible. Also, trajectory tubes can be drawn for the part of the trajectory between trajectory start and current time.
• Required input data:
  • For visual analysis of pre-computed trajectories or particle-ensembles a file with trajectory data is required in a format similar to NetCDF-CF (please contact us for details/examples)
  • For rendering the colours of pre-computed trajectories or particle-ensembles according to pre-computed auxiliary data variables pre-computed auxiliary data variables, these data need to be included as a variable in the NetCDF-CF file with an attribute "auxiliary_data" set to "yes" and the same dimensions as the trajectory vertex information (please contact us for details/examples).
  • For computation of trajectories (streamlines or pathlines) in Met3D, gridded 3-D NWP data with 3 wind velocity components has to be provided 
• GUI interaction:
  • If you are interested in visualizing trajectories or particle-ensembles in Met3D, please do not hesitate to contact us for support. 

How to...

...connect to a trajectory dataset?

• Note that you first need to load a dataset of precomputed trajectories, or configure on-the-fly computation of trajectories. See Actors that manage trajectory data.
• When you first create a trajectory actor, you will be prompted to select a trajectory dataset.
• Alternatively, in the actor properties, select "select data source" - a dialog will pop up from which you can select from the currently available trajectory datasets.

...configure how the trajectories are visualized?

Trajectory data can be visualized in several ways:

• Tubes (as in the sample image above), either showing the entire trajectories (i.e. all time steps) or only part of the trajectories.
• Particles at a specified time step.
• Tubes and particles combined.

To display trajectory data, you need to:

• Select a valid bounding box.
• Select a valid transfer function to have the tubes/particles be coloured according to their pressure elevation or to a selected traced variable.
• Define whether the tubes/particles should be coloured according to pressure elevation or according to a traced variable.
• In the user interface, this will look similar to this: