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Program Basics

The WXP shell often hides the user from the underlying components of WXP.  Each program can be invoked from either the WXP shell or from the operating system shell (such as C shell).  Each program uses resources to define default values and provide resource files, environment variables, command line parameters and program interaction to reset these values.

Each program has online help that can be accessed through the command line with the "-h" option.  Here is the output from "sfcwx -h":

sfcwx: This program plots various types of surface data
sfcwx syntax (version:5.0-AIX-X11)
   sfcwx [options...]
Keyed options...
 -df file    Resource/defaults file name
 -na name    Program name
 -h          Print this help
 -ba         Run program in batch mode
 -me level   Message level to be displayed:
 -nc type    Naming convention file name
 -fp path    File path
 -dp path    Raw data path
 -ti title   Window title
 -ic         Open window iconified
 -bg clr     Background color
 -ge wxh+x+y  Window geometry
Positional options...
 file        Input file name

The help first lists the name of the program and a brief description.  The second line gives the version of WXP (5.0), the binary type (for IBM AIX workstations) and the graphics type (X11 is X windows).  The following lines briefly explain the keyed and position parameters to the program to be invoked on the command line.  To get more information on these, consult the program reference.

The programs use the resources to derive the final product.  These resources define the location of data, naming conventions, the computation to be performed and the look and feel of the output.  The program prompts for those resources that are left unset.  This is done with either a simple prompt or a menu.  If interactivity is not desired, a batch mode can be set which then sets default values for these unset resources.

The input to the programs is generally some specific type of meteorological data.  WXP doesn't group all data into a generic type and provide a single program to access it.  WXP realizes that some data types require special treatment and as a result, programs have been developed around the data such as for surface data, upper air data and model gridpoint data.

The output of the program can either other data files as with decoders, textual as with parsers or graphical as with the plotting and contouring programs.  The graphical output can either be to a window such as with X windows, or a Postscript or HPGL file for printing, or finally a metafile.

WXP programs attempt to provide a consistent interface for setting up the programs, interacting with the programs, and finally the output of the programs.  

For further information about WXP, email technical-support@weather.unisys.com
Last updated by Dan Vietor on June 1, 1998