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WXP Overview

The Weather Processor can be logically divided into three data processing sections: ingest, decoding and analysis. Each of these logical data processing divisions is treated in some detail in subsequent sections.

User Shell

To access the programs, WXP employs a shell called "wxp" which is a menu driven interface into the bulk of the WXP programs.  


  • wxp - The WXP user shell (Unix only)

Data Ingest

WXP needs to get data in order to produce the products.  This data can either be archived or real-time data.  Real-time data access requires a program called an "ingestor" to read in select specific products and save the data into a coherent data structure.

There are two types of ingestors that WXP employs.  The first is the Unidata Local Data Manager (LDM).  This is provided to universities and either ingests data directly from the NWS Family Of Services (FOS) or obtains data over a network from another equivalently setup LDM. This process of transferring data from one LDM to another over the Internet is called Internet Data Distribution (IDD).  

The second type of ingestor is the WXP ingestor.  This is setup to read data from the Domestic Data Plus (DD+), International Data Service (IDS), High Resolution Data Service (HRS) and FAA 604 data circuits. The ingest program saves raw data into user defined data files based on some specified naming convention.


  • ingest - The WXP ingestor
  • scour - A Program to remove older ingested data files

Data Parsing and Decoding

Once the data has been saved to the local disk by the ingest process, it is ready for processing.  In some cases, the data are in a format where parsing it is appropriate.  By parsing, we refer to selecting a specific product from all the ingested data files.  This could be a local forecast, a weather advisory or climate report.  WXP offers several specialized parses to aid in viewing the data.

In other cases, the data are encoded and require some degree of preprocessing before they can be used effectively by other WXP programs.  There are several decoders available to handle various types of data.  In some cases, the encoded data is too complicated to decode every time the data is needed.  Often data of a similar type like surface data are encoded in several similar formats and it would be desirable to have one common format for processing.  There are cases where the information for one site is split up into several products and it would be desirable to have all of that data collated into a single product or data structure for that site. Also, while decoding, there is the opportunity to correct or eliminate erroneous data that is either generated by the observer, the encoding process or through transmission of the data. The new decoded formats also provide a way to get non-standard data processed.  If you have surface data in a format the WXP decoders cannot handle, you can write your own decoder that will produce the WXP format and then be able to plot the data.  This also allows data types such as SAO, METAR, DRIBU and SYNOP to be saved in one format.

Decoders Programs

  • sacvt - The surface data decoder (SAO, METAR, SPECI)
  • smcvt - The surface synoptic data decoder (SYNOP, BUOY, DRIBU, CMAN)
  • uacvt - The upper air data decoder
  • radcvt - The MDR radar data decoder
  • shefcvt - The SHEF data decoder
  • climat - The CLIMAT data decoder
  • tafcvt - The TAF data decoder
  • hurricane - Hurricane advisories decoder

Parsing Programs

  • parse - The general purpose parsing program
  • sa_parse - The surface data parsing program
  • ua_parse - The upper air data parsing program
  • fo_parse - The MOS data parsing program
  • forecast - The forecast parser
  • griblook - The GRIB data parsing program
  • hdrparse - Header file generation program

Data Analysis and Display

The application programs available within WXP can produce a variety of output products. These programs analyze many of the standard meteorological data types including surface, upper air, radar, satellite, model output statistics, and model gridpoint data. These applications use a simple menu structure to guide the user through the different types of data saved in the various types of data files. The analysis programs can plot derived variables such as relative humidity, lifted index and vorticity. The output of these programs can either be plotted data such as a temperature plot or a skew T or it can be contoured plots of gridded fields.  The output devices range from X windows to Postscript printing and metafiles.

Surface Data Programs

  • sfcwx - Plots surface data
  • sfccalc - Contours surface data
  • statlog - Plots time series of surface data

Upper Air Data Programs

Radar Data Programs

  • rad - Plots MDR radar, NIDS, NOWRad and RRWDS data

MOS Data Programs

GRIB Data Programs

  • grbcalc - Contours model gridpoint data (GRIB files)
  • grbsnd - Plots soundings based on model data

Satellite Data Programs

  • xsat - Displays satellite images

Miscellaneous Data Programs

  • light - Plots NLDN lightning data
  • prfplt - Plots Profiler data

Grid Programs

  • contour - Contours existing grids
  • vector - Plots vectors and streamlines from existing grids

Raw Data Programs

  • mapplt - Plots raw data
  • grid - Contours raw data

Mapping Programs

  • mapplt - Plots maps and station locations

Overlay and Looping Programs

These applications work with X windows to provide overlay, annotation and animation capabilities. The wxploop program provides the user with extended overlay, annotation and animation capabilities. The loopset program allows interactive parameter setting with the wxploop program. This allows images to be added or deleted from the loops at any time.


  • wxploop - The annotation, overlay and looping program
  • loopset - The interactive front end to wxploop

Meteorological Calculations

These programs are provided in order to calculate some simple meteorological variables and indices.


  • rawmath - Performs math operations on raw files
  • grdmath - Performs math operations on grid files
  • wchill - Wind chill computations
  • heat - Heat index computations
  • moist - Moisture variable computations
  • stdatms - Standard atmosphere computations
  • suncalc - Sunrise/set computations
  • unit - Unit conversion program
  • domtran - Domain/projection computation program

General Purpose Programs

These programs are used to interface with the other WXP programs.


  • wxpfile - Generates file names, dates, labels, etc
  • wxpdef - Queries WXP resources
  • wxpcity - Queries city, county, state, zone information
  • mc2area - Converts packetized McIDAS data to AREA files
  • pscat - Concatenates multiple WXP postscript files together
  • hpglcat - Concatenates multiple WXP HPGL files together
  • gifcat - Concatenates multiple WXP GIF files together

For further information about WXP, email technical-support@weather.unisys.com
Last updated by Dan Vietor on June 8, 1998