NAME	READ WINDTIMESTAMP -- read the input wind field and timestamp file and
		output a subset field and a subset timestamp string (suitable as
		recursive inputs to this module once the timestamp string is
		written into a file)

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

SUMMARY

	Name		READ WINDTIMESTAMP	

	Type		data input	

	Inputs		input grid		(field 4D uniform float)	
			filename		(string)

	Outputs		output grid		(field uniform 3-vector float)
			datetime		(string)
			nhour			(int)
			output species string	(string)
			current hour		(int)


	Parameters
			Name			Type	Def	Min	Max
			----			----	---	---	---
			USpecies		(choice) " "
			VSpecies		(choice) " "
			starting record		(int)	  1	1	1000
			starting record	time	(string block) NULL
			ending record		(int)	  1	1	1000
			ending record	time	(string block) NULL
			Output Mode		(choice) "Output Single ..."
			go			(oneshot) 0	0	1
			autogo			(toggle)  0	0	1

DESCRIPTION

The READ WINDTIMESTAMP module accepts as input a field of 4 dimensions.  The
input AVS field should be XDR binary 4-byte float (except for interactive
use on CRAY systems where the XDR binary field should be in 8-byte floats).
The second required input is a timestamp file name, and that file should
contain an ASCII list of the date/time labels for each time step in the
input AVS field.  The idea is to create portable data sets that can be read
on the local workstation and have this data treated in the same manner as
that on remote systems.  This is most important for speed considerations.

INPUTS

input grid		input data field of 4 dimensions

filename		full path name of the ASCII timestamp file

OUTPUTS

output grid		output field of either 3 or 4 dimensions, depending
			on the user selected Output Mode; 3 dimensions are
			needed for NEW TILE and "field to mesh" plots while
			4 dimensions are needed for 2D graphs of time series
			information and for NEW TILE or "field to mesh" plots
			of gridded statistical plots (GRID MATH); 3 vectors
			are output: the u vector, the v vector, and the
			calculated wind speed

datetime		string containing the list of date and time labels
			corresponding to the selected record(s) in the
			output grid

nhour			the number of records in the data set
			(needed for ANIMATE DUAL)

output species string	string containing the output species (needed for 
			MINMAX)	-- set to "WIND SPEED"

current hour		the current record in the data set (needed for ANIMATE
			DUAL)

PARAMETERS

USpecies		the u vector selection

VSpecies		the v vector selection

starting record		the starting record number for output

starting record	time	string containing the date and time represented by
			the starting record number

ending record		the starting record number for output

ending record	time	string containing the date and time represented by
			the ending record number

Output Mode		choice of "Output Single Starting Record" or
			"Output Multiple Records"

go			indicator that output should occur 

autogo			indicator that output should occur whenever an input
			or parameter changes

EXAMPLE

RELATED MODULES		

LIMITATIONS

For better coordination with the ANIMATE DUAL module, it might be better
to have matching parameters of current record number, minimum record number,
and maximum record number.  It is a drawback that the 32-bit XDR binary
AVS fields are treated differently on the CRAY than elsewhere and that
special 64-bit versions of data must be created for use there.
 
SEE ALSO

(MCNC Visualization Plan)						11/93
-------------------------------------------------------------------------
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.
-------------------------------------------------------------------------