NAME

Geo::WeatherNOAA - Perl extension for getting NOAA Weather(Wx) Data

SYNOPSIS

use Geo::WeatherNOAA;
print get_currentWX_html('NEW YORK','NY');
print_forecast('NEW YORK','NY');

%wx = get_forecast('BOSTON','MA');
print "The forecast is $wx{NEAR}\n";
print "The extended forecast is $wx{EXTENDED}\n";
print "This information was updated $wx{Date}\n";
print "The affected areas are $wx{Coverage}\n";

DESCRIPTION

I needed a way to get NOAA weather data for both web pages and perl scripts for web pages etc. This module gets information from the NOAA web site and "decodes" it into usable format: hashes, lists, english, etc.

FUNCTIONS

The idea behind these function calls is simplicity. Each function needs at least the city and state. If you want to use the neato cacheing function, give the minutes to cache and, optionally, the directory to use to hold the weather data cache.

• get_forecast(CITY,STATE,CACHE,CACHEDIR,LWP_UserAgent)

  Call with at least to tokens: City and State (Two letter abbr)

  The third token, if used will tell the module to use the caching function so that the data will only be retrieved from NOAA when the cached data is this many minutes old. I figured this would be usefull to a web server where only the first 'hit' would have to wait for the remote data.

  The fourth argument is the directory in which to cache the data. If omitted, the module will use /tmp/wxdata

  The fifth argument is for a user created LWP::UserAgent(3) which can be configured to work with firewalls. See the LWP::UserAgent(3) manpage for specific instructions. A basic example is like this:

  my $ua = new LWP::UserAgent;
  $ua->proxy(['http', 'ftp'], 'http://proxy.my.net:8080/');

  If you merely wish to set your proxy data from environment variables (as in $ua-env_proxy>), simply set

  $Geo::WeatherNOAA::proxy_from_env = 1;

  This function returns a hash with the following keys:

    Coverage 	=> A list of the affected areas for the forecast
    Date 		=> Date/time when the data was reported to NOAA
    NEAR 		=> Newline delineated list, each line contains
  		   a colon (:) delin list of day and data.
  		   NOTE: If there's no data, the "key" is a weather
  		   warning
    EXTENDED 	=> Same as NEAR but without weather warnings
    URL 		=> URL where the data originated

  It can be used like this:

  use Geo::WeatherNOAA;
  %wx = get_forecast('BOSTON','MA');
  print "The forecast is $wx{NEAR}\n";
  print "The extended forecast is $wx{EXTENDED}\n";
  print "This information was updated $wx{Date}\n";
  print "and covers $wx{Coverage}\n";

  In examples/wx.cgi, I split the NEAR and EXTENDED fields to make nicer output:

  use Geo::WeatherNOAA;
  %wx = get_forecast('BOSTON','MA');
  print "<TABLE>\n";
  foreach $line (split "\n", $wx{NEAR}) {
      my ($day,$data) = split /:/, $line;
  
      if ($data) {
          # Normal line if there are both keys
          print "<TR><TD>$day</TD><TD>$data</TD></TR>\n";
      } else {
          # Warning line if there's only the $day value
          print "<TR><TD COLSPAN=2>$day</TD></TR>\n";
      }
  }	
  print "</TABLE>\n";

• print_forecast(CITY,STATE)

  Prints an english (text) description of the forecast

  Its output looks like this:

  	Forecast for BLACKSBURG, VA for March 6, 1998
  
    WARNING: The national weather service has issued a flood watch for
      late tonight through monday
      
    WARNING: A wind advisory has also been posted for very late tonight 
      through monday... 
  
    Tonight: Showers...With a chance of thunderstorms.  Lows in the upper
      40s. South wind around 15 mph. Chance of rain near 100 percent.
  
    Monday: Showers with a chance of thunderstorms...Mainly in the 
      morning.
  
    Turning cooler.  Temperatures falling into the lower 40s. West wind
      around 15 mph.  Chance of rain 90 percent.
      
    Monday night: Mostly cloudy with a chance of rain or snow. Breezy. 
      Lows mostly in the 20s. Chance of precipitation 40 percent.
      
    Tuesday: Partly cloudy with a chance of snow flurries.	
      Colder and breezy. Highs from the upper 20s to near 40. 
      

• get_currentWX(CITY,STATE,CACHE,CACHEDIR,LWP_UserAgent)

  Call with at least to tokens: City and State (Two letter abbr)

  The third token, if used will tell the module to use the caching function so that the data will only be retrieved from NOAA when the cached data is this many minutes old. I figured this would be usefull to a web server where only the first 'hit' would have to wait for the remote data.

  The fourth argument is the directory in which to cache the data. If omitted, the module will use /tmp/wxdata

  The fifth argument is for a user created LWP::UserAgent(3) which can be configured to work with firewalls. See the LWP::UserAgent(3) manpage for specific instructions. A basic example is like this:

  my $ua = new LWP::UserAgent;
  $ua->proxy(['http', 'ftp'], 'http://proxy.my.net:8080/');

  If you merely wish to set your proxy data from environment variables (as in $ua-env_proxy>), simply set

  $Geo::WeatherNOAA::proxy_from_env = 1;

  This function returns a hash with the following keys:

  CITY		=> Name of reported city
  SKY/WX	=> Sky conditions
  TEMP		=> Current temp
  DEWPT		=> Dewpoint
  RH		=> Relative Humidity
  WIND		=> Wind direction and speed
  PRES		=> Pressure
  REMARKS	=> Remarks

• get_current_html(CITY,STATE,CACHE)

  Call with at least to tokens: City and State (Two letter abbr)

  The third token, if used will tell the module to use the caching function so that the data will only be retrieved from NOAA when the cached data is this many minutes old. I figured this would be usefull to a web server where only the first 'hit' would have to wait for the remote data.

  This call returns a scalar containing a (sort-of) htmlized english sentence describing the weather in the requested city.

  use Geo::WeatherNOAA;
  $weather = get_currentWX_html('RICHMOND','VA');
  print "$weather\n";

  The output looks like this:

  At 8:00pm EST, Richmond, VA was experiencing cloudy skies at 66°F,
  wind is south at 15mph. 

AUTHOR

Mark Solomon

msolomon@seva.net

http://www.seva.net/~msolomon/wx/

SEE ALSO

perl(1), LWP(3), LWP::UserAgent(3).