Using wview

 in
If knowing what the weather is gets your blood pumping and your heart racing, you need to get wview and hook it up to your other great passion, which is, of course, Linux.
Default Web Site

If all is well, you now can view the default wview weather site. This is typically found at http://[your_server_url]/weather/index.html (Figure 5).

Figure 5. Default Web Site

Current conditions are given in the table on the left and by the dials in the center and on the right. These values are updated every time station data is polled (default is 30 seconds). The weather site pages are regenerated every 60 seconds (configurable). Observing changes in the current conditions is an easy way to confirm proper station interface operation.

Historical data for the last 24 hours are presented as graphs. Graphs of the last 24 hours, the last 7 days, the last 28 days and the last 365 days are available on other site pages.

Citizen Weather Observer Program (CWOP)

CWOP is a system by which individuals with weather stations and the proper software can submit their weather data to an APRS-based data storage system, so that others, including NOAA (National Oceanic and Atmospheric Administration), can use the data however they see fit. There are some really neat station display Web sites, including some Java apps to look up station data, position, maps and so on. See www.findu.com/cgi-bin/wxpage.cgi?call=CW4097 for an example weather station.

CWOP participation requires registering for an APRS callsign. Once you have configured wview for CWOP properly and confirmed your data on-line, you must contact the maintainers via e-mail to confirm your registration. Then your data will be available for anyone to see and possibly be used in NOAA forecast models and so on.

When CWOP support is enabled and configured properly, wview transmits a new WX packet to the APRS server every ten minutes, based on the last digit of your callsign.

wview supports the APRS-IS Rollover (Automatic Packet Reporting System-Internet Service) functionality by enforcing the definition of three APRS-IS server:port pairs. The goal is to avoid data loss to the CWOP system caused by connection errors. Select three different servers from the list at www.wxqa.com/activecwd.html.

Click the Services tab and enable CWOP submission and CWOP verbose logging. Click Save Changes. Next, click the CWOP tab, and enter your callsign, latitude and longitude (see the mouse-over help for format details), the CWOP servers (three should be entered) and port numbers. Go ahead and enable “Log CWOP Packet?”; you can disable it after submission is confirmed. Click Save Changes.

Now, restart wview:

$ sudo /etc/init.d/wview restart

You can monitor CWOP packet submission in the system log (and on the CWOP status pages).

Weather Underground

The Weather Underground (Wunderground) is a privately held organization that provides many weather services—some free and some not. Among the free services is the ability to register your weather station and submit your data to them, so you can access your data and some nice graphs from the Wunderground site. Weatherforyou.com also is a privately held outfit with similar capabilities to Wunderground.

Register for a Weather Underground Station ID (unless you already have one) at www.wunderground.com/weatherstation/usersignup.asp. Determine your accurate latitude and longitude: www.topozone.com/viewmaps.asp.

Click the Services tab and enable the HTTP service. Click HTTP Services and configure the Weather Underground settings. Click Save Changes.

Look in the system log for something similar to:

"WUNDERGROUND: configured to submit \
               station KTXCOLLI1 data to wunderground.com"

Confirm your data at the Wunderground server: http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=XXXXXXX, where XXXXXXX is your Wunderground Station ID. This should start displaying your weather data graphically and as a packet list.

Data Archive and External Applications

A number of simple open-source weather station applications are available that do little more than extract the data from the weather station and archive it for later post-processing or retrieval by another server for multisite analysis. Researchers wanting to gather weather data for their own purposes is one example of such an implementation.

It is often (incorrectly) asserted that wview is “more application” than is needed for simple archival purposes. In fact, wview allows for much configuration as to “how much” it does for you. Designed as a series of loosely coupled UNIX processes, wview easily can be configured as an archive-only server. It also is easy to add CWOP and/or Wunderground/Weatherforyou to the archive server—all without any “fancy” HTML or other file generation. If you don't want to generate a Web site, you don't have to have one!

After installation and typical configuration, disable all wview Processes (under the Services tab in wviewmgmt). The station interface process always is enabled and, thus, is not configurable. Start wview as normal. Only the wviewd_<station> dæmon will be running, collecting data from the station and archiving records and HILOW values in the archive databases.

Because wview stores archive data in SQLite3 databases, it is a simple matter to implement scripts or applications that access the data via SQL. Many wview users create their own custom Perl/PHP/Java/WordPress applications for their weather data.

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