VectorDisplay

DESCRIPTION

This module creates a geometric representation of vector data. It creates lines and arrows to show the direction and magnitude of each vector. The geometry of each vector may be colored according to its magnitude (or the magnitude of its horizontal and vertical components), its vertical position, or the local value of an additional scalar field. The thickness of the lines may be interactively controlled. The display of vectors having zero length may be toggled on or off.

Acknowledgement

Portions of this module were originally developed at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign.

THE UNIVERSITY OF ILLINOIS GIVES NO WARRANTY, EXPRESSED OR IMPLIED, FOR THE SOFTWARE AND/OR DOCUMENTATION PROVIDED, INCLUDING, WITHOUT LIMITATION, WARRANTY OF MERCHANTABILITY AND WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE.

INPUTS

Port: Vector Field In
Type: Lattice

The vector field to be depicted. If the data field has fewer than three components, the vectors will be depicted as if the missing components are zero. If there are more than three components, the additional components will be ignored.

Port: Scalar Field In
Type: Lattice
Optional: This port is optional.
Constraints: 1-vector

A scalar field on which to base the coloring of the displayed vectors. This field is used only if the "Color by Scalar Field" option is chosen for the 'Coloring' parameter - see below. Note that the dimensions of this field must exactly match those of the vector field. The values from this field are used to extract colors from the color map.

Port: Color Map In
Type: Lattice
Optional: This port is optional.

A color map to be used to color the vectors. If this is not provided, a default color map adapted to the appropriate range of data values is used. This default map supplies a smooth range of colors from magenta (lowest values) through blue, cyan, green, yellow and red (highest values).

WIDGETS

Port: Scale Factor
Type: Slider

Scale factor to be applied to the vector field geometry. This determines the relative length of the line or arrow that depicts each vector. When this value is set to 1.0, the length of the displayed line or arrow is equal to the magnitude of the vector data.

Port: Vector Style
Type: Option Menu
Menu Item: Line
Menu Item: Line Arrow (2)
Menu Item: Line Arrow (4)
Menu Item: Cross Arrow
Menu Item: Solid Arrow
Menu Item: Fade Line

This parameter indicates how each vector should be represented:

Line           - A single solid line.
Line Arrow (2) - An arrow with a two-pronged head.
Line Arrow (4) - An arrow with a four-pronged head.
Cross Arrow    - An arrow with a head consisting of two solid triangles.
Solid Arrow    - An arrow with a head consisting of a solid pyramid.
Fade Line      - A single line that is bright at the base and dim at the head.

Port: Arrow Head Size
Type: Dial

Scale factor to apply to the size of the arrow head.

Port: Coloring
Type: Option Menu
Menu Item: White
Menu Item: Black
Menu Item: Color by Magnitude
Menu Item: Color by Vertical Magnitude
Menu Item: Color by Horizontal Magnitude
Menu Item: Color by Vertical Level
Menu Item: Color by Scalar Field

This parameter determines how the vectors are to be colored:
White                         - All vectors are colored white.
Black                         - All vectors are colored black.
Color by Magnitude            - Apply the color map based on the 3D magnitude
                                of each vector.
Color by Vertical Magnitude   - Apply the color map based on the value of the
                                third component of each vector.
Color by Horizontal Magnitude - Apply the color map based on the magnitude of
                                the 2-vector formed by the first two components
                                of each vector.
Color by Vertical Level       - Color the vectors based on the Z coordinates of
                                their location.
Color by Scalar Field         - If a scalar field of the same dimensions as the
                                vector lattice is provided, this option will
                                color the vectors based on the corresponding
                                values of the scalar field and the color map.
                                This option is disabled if there is no
                                connection to the 'Scalar Field In' input port,
                                or if there is no data on this port; selecting
                                this option in that case will result in the
                                vectors being colored white.

Port: Adapt Vector Scale
Type: Button

If this button is pressed, the vectors are scaled so that the length of the longest vector is appropriate for the spacing between lattice points. The Scale Factor widget is adjusted to reflect the new scale.

Port: Adapt Arrow Head Size
Type: Button

If this button is pressed, the size of the arrow heads are scaled so that they are appropriate for the spacing between lattice points. The Arrow Head Size widget is adjusted to reflect the new scale.

Port: Line Width
Type: Dial

Line width (in pixels) used when creating the output geometry.

Port: Zero Vector
Type: Check Box

Control over display of zero-length vectors. If this parameter is turned 'Off', any vectors having a length (magnitude) of zero will not be displayed. Turning it 'On' will cause them to be displayed if the 'Vector Style' parameter is set to one of the 'arrow' options (if it's set to one of the other options, they still won't be displayed since the length of the displayed line is proportional to the length of the vector).

OUTPUTS

Port: Vector Geom Out
Type: Geometry

The geometric representation of the vector field.

KNOWN PROBLEMS

The "Adapt Vector Scale" and "Adapt Arrow Head Size" features will not work well when grid points are very irregularly spaced.

SEE ALSO

Vectors, VectorGen


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