Specifying Flow seeds with Probe

VAPOR GUI supports an interactive means of exchanging coordinates between the Probe and the Flow tabs, which is useful for performing precise analysis of flow behavior. 

• Using the probe, users can identify points based on the value of variables that can influence flow behavior, such as flow magnitude, vorticity, temperature, etc. 
• These points can be identified by clicking the Probe cursor, and viewing the position in both 2D and 3D visualization. 
• The identified points are supplied to the flow, and are then used as seed points in the flow integration, resulting in immediate construction of flow lines or path lines passing through the points.
• The new flow lines are visualized as they are constructed.
• As flow lines are identified that exhibit interesting behavior, the corresponding seed points are saved.

Note that VAPOR GUI also supports the use of the 2D tab and the Image tab to specify flow seed points.

The following image illustrates magnetic field lines in a flux tube that are constructed using the Probe:

Several examples of this process are provided in VAPOR documentation.  For example, in the Hurricane Katrina Tutorial, a Probe of the vertical wind speed is used in conjunction with flow integration to help explain the dynamics occurring near the eye-wall of the hurricane.  In the VAPOR Quick Start Guide, magnetic field lines through a magnetic flux tube are constructed using a probe of magnetic field strength.  In the Georgia Weather Case Study, a probe is used to specify seeds for wind flow, enabling construction of stream lines and particle traces near the terrain surface.