NAME
	draw tracks - Convert 2/3-vector field to 2D geometry

AUTHOR INFORMATION
	John Tee
	AVS Inc. Consultant
	17 Dawnay Road, Great Bookham, Leatherhead, Surrey KT23 4PE, UK

SUMMARY
	Name	draw tracks
	Type	Mapper
	Inputs	input - 		field 2-vector float
		pick information 	struct upstream geometry
                colormap                used to color the track lines
	Outputs	tracks -	geometry
	Parameters
	Name		Type	Default		Min/Max
	info		text
		

DESCRIPTION:
    DRAW TRACKS is a module provided to demonstrate the use of the
geometry viewer to display two-dimensional track information provided
as a floating point 2-vector (x,y) input field.  If the input field has
more than one dimension, multiple tracks are displayed.
If the field is 3-vector, it uses the third vector component to
color the lines, with the optional colormap input field.
The hi-low dials of the colormap control the line color range.

DRAW TRACKS also allows the user to select a track of interest by
clicking the mouse on it.  The selected track is highlighted by changing
its colour, and the selected vertex is indicated by positioning a sphere
over the vertex, and a line connecting the vertex to the sphere.  The
coordinates of the selected vertex are displayed in a text window.


INPUTS
	input - field 2-vector float
             or       3-vector or more

OUTPUTS
	tracks - geometry
	info -	 text display of picked coordinates

PARAMETERS
	info
displays the coordinates of the picked vertex

EXAMPLE 1
	The network test_draw_tracks uses DRAW TRACKS.

LIMITATIONS
	The module could trivially be converted to display 3D tracks.