GRID MATH -- create a single gridded representation of statistical functions over multiple time steps

Name

GRID MATH -- create a single gridded representation of
			statistical functions over multiple time steps

Author

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

Summary

	Name		GRID MATH	
	Type		filter	
	Inputs		input field	(field 4D 3-coordinate uniform float)	
	Outputs		output field	(field 3D 3-coordinate uniform float)	
			output string	(string)
	Parameters
			Name			Type	Def	Min	Max
			----			----	---	---	---
			math function		(choice) MIN	--	--
			compliance level	(float)	 0.0	UNBOUND	UNBOUND

Description

The GRID MATH module takes 4-D input and creates 3-D output based upon the
selected statistical function.  The effect is to reduce multiple time
dimensions to a single one representing the chosen math function.

Inputs

input field	multi time steps of 3-D gridded data values (4D)

Outputs

output field	3-D output of gridded values of specified statistical
		calculations over all time steps
output string	a label indicating the first and last time stamp represented
		by the calculation, in essence a time-span label

Parameters

math function	statistical function performed over all time steps;
		choices include MIN, MAX, MEAN, HR MIN OCCURRED,
		HR MAX OCCURRED, and HRS OF NON-COMPLIANCE (in which
		the grid cell values exceeded the "compliance level")
compliance
 level		the value set above which grid cells will be deemed out of
		compliance

Example

Related modules

Limitations

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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