| iTool User's Guide: Working with Vectors |

## Streamlines

Streamlines visualize the movement of a set of massless particles through the vector field. The points are tracked by treating the vector field as a velocity field and integrating it. Each path is tracked until the path leaves the input field or a maximum number of steps is reached. You can use keywords to set the number of particles, the integration step size, and the number of steps.

The following example shows the streamlines produced by a random vector field. To create these streamlines in IDL, enter the following code at the Command Line:

    u = RANDOMU(1,20,20) - 0.5
    v = RANDOMU(2,20,20) - 0.5
    IVECTOR, u, v, /STREAMLINES, $
       X_STREAMPARTICLES=10, Y_STREAMPARTICLES=10, $
       HEAD_SIZE=0.1, STREAMLINE_NSTEPS=200

Figure 16-3: Streamlines in iVector

Figure 16-3: Streamlines in iVector

Note For details on the streamline keywords, see IVECTOR. Also see Adding and Modifying Streamlines.

IDL Online Help (March 01, 2006)