WA8LMF Home Page | Main Ham Radio Page | Main APRS Page | Updated  10 Oct 2012

 

Using US National Weather Service Shapefiles With APRS

Win/MacAPRS, APRSplus and UIview can highlight areas under a US National Weather Service warning for counties and zones without using an individual map for each area. This is done by overlaying colored outlines on existing APRS maps. These outlines, known as "shapefiles", are in the native format of the ESRI Arcview professional GIS program widely used by government agencies and civil engineers.  These shapefiles are also directly readable by the four APRS programs mentioned above, as well as many other mapping, CAD and vector-draw applications.

The data required to light up these filled outlines on APRS maps was formerly transmitted continuously by a special server maintained by Dale Huguley, KG5QD. It intercepted official NWS messages, and reformatted them into APRS-compatible format. The messages were inserted into the APRS Internet System, as APRS bulletins, by a "virtual igate" called "WXSVR". Details on these messages and their format is located here:

        http://www.aprs-is.net/Wx/      

Note:  Australian APRS users have created a similar WXSVR-AU which provides a nearly identical service in Australia. This service shares the Internet feed with the U.S. version, and works with the same UI-NWS plug-in for UIvew as it's American counterpart.  Details on the Australian version of the weather server are here:

        http://wxsvr.aprs.net.au/  

As of mid-July 2009, the original WXSVR that injected the NWS alerts into the APRS Internet System to make the NWS shape file feature work shut down.  A replacement  server, AE5PL-WX, is now online providing this service. Shapes and symbols for severe weather WARNINGs should appear on maps just as before.

However, the operator of the new weather server has opted to vastly reduce the volume of traffic inserted into the APRS Internet System.  This is to reduce the local radio channel congestion when these bulletins are retransmitted on RF.  AE5PL-WX only transmits WARNINGS (severe weather actually in progress) but not the ALERTS and WATCHES sent by the old server. 

As a result, you will never see the yellow ALERT areas and orange WATCH areas that formerly appeared on UIview maps. Only the far less numerous red WARNING shapes will appear, and for shorter periods of time.  

UPDATE AS OF SPRING 2011:   Another source of the NWS alerts, that duplicates the full feed of the original WXSVR is now available.   "FireNet" is a separate server system operating in parallel with the standard APRS-IS.  It provides the full APRS-IS feed, plus hundreds of other objects of interest to SAR groups, disaster incident commanders. EOC managers and others.  FireNet includes earthquake epicenters, forest fires, stream and river water gauges, and the full NWS weather feed.

Just insert  firenet.us port 14580 into your APRS software server login setup, instead of a "normal" APRS server.   In UIview, this would be added to the APRS server list in the "APRS Server Setup" dialog by using the keyboard "Ins" (Insert) key and entering  
firenet.us:14580  and then checking the box to enable the new entry..  The standard port 14580 user-defined filter commands work on FireNet .

More details on FireNet are here:  http://info.aprs.net/index.php/FireNet

 

Note that there are three kinds of weather items that can appear on APRS maps:

  • Discrete APRS symbols (a.k.a. "icons") of floods, storms, tornados, etc. 
    (You MUST have the current APRS symbol set installed. for these to display properly. Using the outdated symbols provided "original equipment" with WinAPRS, UIview or APRSplus will cause the WRONG symbols to display during these warnings.)

     
  • Hollow outlines of affected areas, sent as standard APRS vector-drawing  "area" objects.

    (No special settings or added downloads are required to display either of these -- just a an APRS Internet feed that passes the feed from the weather data server.  These first two types of objects will show on any APRS map covering the relevant area in UI-View, even without the UI-NWS option IN UI-View running.)
     
  • The transparent colored "shape file" overlays of warning regions that DO require the added downloads below.

    (In UI-View, the UI-NWS option must be running, and the necessary shape files downloaded and installed, for these to show on maps.
    )

Using the right-click "finger" function to retrieve the full text of NWS bulletins in UIview will require editing the two files UIview32.INI and  UINWS.INI  located in the main UIview program folder. 
 

  • Shut down UIview.
  • Locate the string  FQDN=WxSvr.net  in each file, and replace it
    with 
    FQDN=wx.aprs-is.net .
  • Restart UIview.

These NWS bulletins are received over a normal APRS Internet server connection. Bulletins for the entire country will be received even on regional-filtered APRS feeds.   Normally these bulletins are not transmitted over APRS RF. (You must have an Internet connection to receive them.) 

If you use the port 14580 user-defined filter port on an APRS server, adding  "
t/n" to the normal port 14580 filter expression will cause the weather server data to be sent to you.  You will receive all of the NWS bulletins for the entire country, even if you are filtering normal APRS position reports to a limited area. For details on filtering the NWS data stream, see the  Filtering the NWS Feed sidebar below.


Three sets of files for county outlines, standard NWS warning areas, and coastal marine zones are required.  The county outlines are fairly stable but the warning zones change frequently ( one or two times a year ) These files are downloaded from the NOAA/NWS website.
 

As of the time of writing of this page, the specific files needed are located at:
 

These files need to be downloaded and unzipped into the appropriate folder for the program in question.  

Filtering The NWS Feed

By default, the filter port switch t/n sends you ALL the NWS bulletins for the entire US and Australia (which has recently implemented WXSVR-AU which works in exactly the same way as the US version).  Any and all warning regions within the coverage of your map will light up.

To reduce clutter (or to reduce consumed bandwidth on a wireless Internet device), you may wish to restrict the data sent to you.

Users in the US can remove the Australian WXSVR-AU feed by adding
-e/WXSVR-AU to their port 14580 filter expression.

Since the WX alerts are sent as APRS bulletins (i.e. messages without lat/long info) rather than APRS position reports, the normal filter port range filters based on distance from a particular position WILL NOT WORK.  (The geo-spatial position information is already stored locally in the database archives containing the shape files. All that is transmitted in the warning message is a shorthand code that "wakes up" the appropriate stored shape file outline(s) for display.

However, the bulletins for each regional NWS office are sent from a different virtual "callsign". This "callsign" shows in the "From:" field of NWS listings, or when you double-click a displayed alert on the map in UIview.   Note that these virtual callsigns refer to particular NWS regional offices, not individual warning zones.  You may see more than one shape originating from the same office. A single NWS office can be responsible for multiple warning zones, such as flatlands, valley bottoms, mountain foothills, mountain high country, several counties, etc (i.e. anywhere weather patterns differ within a single NWS office's jurisdiction).  

Wait until the regions of interest "light up", identify the originating "callsign" for these areas, and then create a port 14580 filter for "
b/" ("budlist a.k.a. Buddylist; i.e. a list of specific callsigns to pass regardless of location). 

This might look like
      
filter   b/GRRWSW,IWXWSW     (selects most of western and central Michigan including my home town of East Lansing, and northern Indiana.).  

Remove the global select
t/n from the filter expression. 

Note that, since the filter port expressions are additive, you can still have other filters such as distance filters based on your own location or specific points, area filters based on lat/long boxes, etc. 

Details on the port 14580 filter options are here this website:

Filter Port Guide