NAME	QUERY TILE -- create a geometry of a cross hair cursor over a tile
		 plot and report the value of the point at that tile position

AUTHOR	Kathy Pearson, MCNC, kathyp@mcnc.org, (919) 248-9240

SUMMARY

	Name		QUERY TILE	

	Type		mapper	

	Inputs		input_field	(field uniform float)	
			slice axis	(string)

	Outputs		geom_output	(geometry)

	Parameters
			Name		Type		Def	Min	Max
			----		----		---	---	---
			X Point		(int)		1	1	256
			Y Point		(int) 		1	1	256
			Z Point		(int)		1	1	256
			Query		(toggle) 	0	0	1
			Answer		(string block)  NULL
			Cursor Red	(float) 	1.0	0.0	1.0
			Cursor Green	(float) 	1.0	0.0	1.0
			Cursor Blue	(float) 	1.0	0.0	1.0
			Cursor Z	(float) 	100.0	0.0	UNBOUND

DESCRIPTION

The QUERY TILE module accepts as input a field sliced on "X", "Y", or "Z"
and displays a cross hair cursor to be used in conjunction with the NEW TILE
module.  The module reports in the Answer string block the coordinates and
the value of the point indicated by the cross hair.  The Query toggle is
used to turn on and off the query geometry cross hair.  The Query position
is determined by the slice and the other 2 of 3 coordinates, X Point, Y Point,
and Z Point.

INPUTS

input_field		input data field sliced on "X", "Y", or "Z"

slice axis		"X", "Y", or "Z" slice axis

OUTPUTS

geom_output		color cross hair output geometry 

PARAMETERS

X Point			x coordinate of Query position

Y Point			y coordinate of Query position

Z Point			z coordinate of Query position

Query			switch indicating that Query geometry & reporting
			requests are to be on/off	

Answer			string block widget to contain the answer to the
			Query in the form "tile(X,Y,Z) = Value"

Cursor Red		red component of cross hair color

Cursor Green		green component of cross hair color

Cursor Blue		blue component of cross hair color

Cursor Z		(defunct) the layer assigned to the geometry cross hair

EXAMPLE

RELATED MODULES		NEW TILE

LIMITATIONS

The usefulness of this query function is questionable.  Its use with "field
to mesh" may not be appropriate, especially with slices other than Z.  A
better probe function that relies on a single mouse click instead of a set
of dials would be more ideal.
 
SEE ALSO

(MCNC Visualization Plan)						11/93
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The MCNC Environmental Programs Group has created this module as part of a
suite of AVS demo modules, networks, and sample data sets to demonstrate 
the functionality of its visualization prototype for an Environmental 
Decision Support System (EDSS).  This system provides a unified method of 
analysis and visualization for data output from different environmental air 
quality models.  Remotely, standard output files from the following models 
can be read into AVS:

        ROM (Regional Oxidant Model)
        RADM (Regional Acid Deposition Model), low res and high res
        RADM (Regional Acid Depostion Model) Emissions, low res
        UAM (Urban Airshed Model, regulatory version)
        UAM (Urban Airshed Model, AREAL research version)
        UAM Wind (Urban Airshed Model, regulatory version)
        MCNC ALPHA-Prototype netCDF files

Alternatively, xdr portable binary AVS fields can be created from these
data types and accessed directly from the local workstation.

You can download these modules individually from the IAC using anonymous
ftp to the appropriate directories /avs_modules at avs.ncsc.org.  
If you would like to download the entire suite of modules, networks, and
sample datasets at the same time, the IAC recommends that you use 
anonymous ftp to grab the following file from avs.ncsc.org -

/sample_data/avs_data/MCNC_Env_Pgms/MCNC_Env_Pgms.tar.Z

This contains all source code to all local and remote modules, as well as
all of the sample datasets, networks, documentation, installation, and
usage notes.
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