4 Pathlines shown at 5 different time values
4 Pathlines shown at 5 different time values

Particle traces calculated in a Transient Data flow field are called pathlines.


Pathlines are simply Streamlines computed in a Transient Data flow rather than steady-state. Because of this, all computations and derivates must take into consideration the additional fourth dimension of the data - Time. This makes pathlines considerably more time-consuming and complex than streamlines, but more useful in analyzing flow over time.

A pathline in steady-state flow is identical to a streamline.


Pathlines are useful for visualizing the flow of an individual particle across time. Such uses for this include:

  • Analyzing the paths of drifting debris in oceanographic data
  • Analyzing paths of airborne debris or pathogens in atmospheric data

Visualizing a pathline is more difficult than a streamline, as each point coincides with not only a location but an additional time value. Because of this, visualization is typically as an animation, or as a time with annotated time information.

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