APRS+SA NWS Tab
Purpose - decoding, displaying, and mapping of NWS Weather related messages.

The NWS messages that APRS+SA decodes are generated by a server written by Dale Huguley, KG5QD.  These message are in the following format. This information is from the following URL: http://www.ae5pl.net/html/nws_databases.htm.

CWAPID>NWS-TTTTT:DDHHMMz,ADVISETYPE,zcs{seq#

CWA is the NWS office (See databases to the left).
PID is the product Code (See database to the left).
TTTTT is ADVISE, WARN, WATCH, etc.
DDHHMMz is the expiration time.
ADVISETYPE is things like FLOOD, FLASHFLOOD, SVRTSM, SEVERE_WEATHER, etc.
zcs are the zone codes, county codes (See databases to the left), or statement text.
{seq# is decoded as:

The first three characters are the "issue time" compressed by assigning 0-9 as themselves A-Z as 10 thru 36 a-z as 37 - 62 --where it is DHM (Day of the Month-Hour in 24 hour format and Minute). Up to 16 this reads as hexadecimal so {A8B** was issued on the 10th at 08:11 Z.

The next two characters are line numbers which (along with the "From Call" ) make the packet unique.  Any packet with the "from Call" and the first 4 digits of the sequence matching are "associated" packets- in otherwords they are from the same product or portion of product that is defined by UGC codes.

The final character is for sorting and for assigning some priority to the various outputs (objects, headlines, packets that highlight counties, background info).


The APRS+SA NWS tab the following columns:
------------------------------------------
From, To, Expires, Type, Zones/Codes, Posted, Sequence, and Path.

From:  This is the CWA of the NWS office, and PID
To: is the TTTTT, or level of warning
Expires: is the Expiration time of the message
Type: is the ADVISETYPE
Zones/Codes: are the zone and county codes.  There can be multiple zones or counties in one message.
Posted: This is the date/time the message was posted. This is taken from the Sequence number
Sequence: is the sequence number of the message.
Path: is the APRS path by which the packet was received.


NWS TOOLBAR
Map Button: This button calculates a map Overlay from the Zones and Codes of decoded messages, and them generates a map from this overlay.

Menu Button: Use Shapefiles - This option tells APRS+SA to look for and use the "Shapefiles" for drawing either a rectangle or an outline border around the warning area.  These "Shapefiles" are available online from the NWS.  A Shapefile is a standard of ESRI, which produces GIS products such as ArcView.  A Shapefile is actually 3 files, a DBF database file, a SHP file which contains the various "shapes", and a SHX file which is an index into the SHP file.  These files are quite large, but contain all the information for CONUS and non-CONUS areas covered by the NWS.  They can be downloaded from the locations below.  Note, the NWS does update these files periodically, and the actual file name can change.  The main NWS Map catalog is located at: http://isl715.nws.noaa.gov/mapdata/newcat.  The files needed are the Zone Forecast Areas, and AWIPS Counties, not the County Warning Areas.  Here are the links to the current Zone and Code files used by APRS+SA.
http://isl715.nws.noaa.gov/mapdata/newcat/amdc/wsom/z_16mr01.zip
http://isl715.nws.noaa.gov/mapdata/newcat/amdc/county/c_24ja01.zip
These files should be unzipped into the NWS directory.
APRS+SA can still draw warning areas using circles centered on the various regions with a radius the covers the area.  The files for this data are the same ones that I produced for use with APRSdos named Codes.txt and Zones.exe.  This are automatically installed into the NWS directory when you run the APRS+SA SETUP.EXE program. Note: when APRS+SA first uses either the Shapefiles or the Codes/Zones files, it much first calculate the indexes.  This may cause the program to pause momentarily while the indexes are calculated.  They are calculated only once after starting the program.

Menu Button:  Use Boxes instead of Outlines from Shapefiles - If you are using the NWS Shapefiles, you can generate a rectangle the covers the area of warning instead of outlining the specific zone and code areas. You would use this option for speed only.

Menu Button: Text to Speech - This tells APRS+SA to use Microsoft's Agent to speak out the warning message.

Menu Button: Morse Code - This tells APRS+SA to generate a Morse code message of the PID code for decoded messages.

Menu Button: Map All Incoming packet on the Overlay - This option causes APRS+SA to include all decoded Zones and Codes in the NWS Overlay map.  

Menu Button: Recalculate Overlay - This causes APRS+SA to recalculate the Overlay map data for the all the messages received.  You might use this option if you change which files you are using, Shapefiles or not, or whether you change from drawing Boxes to Outlines.

Menu Button: Map Overlay - this causes APRS+SA to draw a map with the current NWS Overlay Map data

Menu Button: Clear Page - this clears the entire NWS tab, it does not clear the current overlay

Menu Button: Clear Overlay - this clears the current NWS Overlay map data, but does not clear the NWS tab.

Zones/Codes: In this slot, you can enter the various codes and zones you want to decode.  You can use Wildcards, and you can multiple specifications separated by either a space or a comma.  Example:  CA* AZ* NV*.  This would decode all messages for Zones and Codes in California, Arizona and Nevada.  When a packet is decoded which passes the specification you provide, APRS+SA will 1) Draw a map centered on the area of warning, 2) will generate a audio, Text-to-Speech message is Speech is enabled, and 3) will generate a Morse code message for the PID if Morse is enabled.  Decoded packets are added to the NWS Map Overlay.  

Mapping note: to get all of the mapped Zones and Codes to be included in view, check the "Zoom Includes Tracks" option on the APRS tab in the appropriate MOP file for the map being drawn. If you do not use MOP files, then the default MapOptions.MOP is used, and you can check the Zoom option on the APRS tab of the MOP window.

Thanks to Pete Loveall, AE5PL for providing information on the NWS Shapefiles and NWS Message format.  Thanks to Dale Huguley, KG5QD for the NWS Server data.  And to Hasan Schiers, N0AN for his hours of testing and feedback.
