XML is a great choice for distributing data. That is
probably why the National Weather Service (NWS) has chosen XML as the format to
distribute their current weather conditions for about 1,800 locations in the United States. These feeds are updated hourly and come in both XML and RSS formats. The
focus of this article will be using the XML feeds to display current local
weather conditions on your web site.
The first step is to go to the NWS web site using this link. Once you are at the
NWS site, to find your local weather station just select a state and then
select the orange and white XML image next to the location that you want to display
in the XML column. There are two columns of XML images; the first column contains
a link to the RSS file, the second column links to the XML file and that is the
one you want. What you are looking for is the four character station ID. In my
example I will be using the station ID for Chicago's Midway Airport which is KMDW. Once you click on the link, the XML feed will be displayed in your
browser. It will look similar to Listing 1 for Midway Airport. The URL for the
XML feed you have chosen will be in your web browser's address bar. You will
need to write down or copy and paste this URL so that we can use it when
building our web page.
Listing 1 shows a snapshot of an actual XML feed for Chicago's Midway Airport. This snapshot was taken from this URL. The URL you
saved should look identical except for the four character station ID. Taking a
look at the different nodes in the listing will give you an idea of what
current weather conditions can be displayed.
Listing 1 - This is a copy of the XML feed for
Chicago's Midway Airport
<?xml version="1.0" encoding="ISO-8859-1" ?>
<current_observation version="1.0"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation=
"http://www.weather.gov/data/current_obs/current_observation.xsd">
<credit>NOAA's National Weather Service</credit>
<credit_URL>http://weather.gov/</credit_URL>
<image>
<url>http://weather.gov/images/xml_logo.gif</url>
<title>NOAA's National Weather Service</title>
<link>http://weather.gov</link>
</image>
<suggested_pickup>15 minutes after the hour</suggested_pickup>
<suggested_pickup_period>60</suggested_pickup_period>
<location>Chicago Midway Airport, IL</location>
<station_id>KMDW</station_id>
<latitude>41.47.03N</latitude>
<longitude>087.45.19W</longitude>
<observation_time>Last Updated on Jan 5, 7:51 pm CST</observation_time>
<observation_time_rfc822>Fri, 5 Jan 2007 19:51:00 -0600 CST
</observation_time_rfc822>
<weather>Overcast</weather>
<temperature_string>50 F (10 C)</temperature_string>
<temp_f>50</temp_f>
<temp_c>10</temp_c>
<relative_humidity>74</relative_humidity>
<wind_string>From the North at 6 MPH</wind_string>
<wind_dir>North</wind_dir>
<wind_degrees>340</wind_degrees>
<wind_mph>5.75</wind_mph>
<wind_gust_mph>NA</wind_gust_mph>
<pressure_string>29.67" (1005.0 mb)</pressure_string>
<pressure_mb>1005.0</pressure_mb>
<pressure_in>29.67</pressure_in>
<dewpoint_string>42 F (6 C)</dewpoint_string>
<dewpoint_f>42</dewpoint_f>
<dewpoint_c>6</dewpoint_c>
<heat_index_string>NA</heat_index_string>
<heat_index_f>NA</heat_index_f>
<heat_index_c>NA</heat_index_c>
<windchill_string>48 F (9 C)</windchill_string>
<windchill_f>48</windchill_f>
<windchill_c>9</windchill_c>
<visibility_mi>10.00</visibility_mi>
<icon_url_base>http://weather.gov/weather/images/fcicons/</icon_url_base>
<icon_url_name>novc.jpg</icon_url_name>
<two_day_history_url>http://www.weather.gov/data/obhistory/KMDW.html
</two_day_history_url>
<ob_url>http://www.nws.noaa.gov/data/METAR/KMDW.1.txt</ob_url>
<disclaimer_url>http://weather.gov/disclaimer.html</disclaimer_url>
<copyright_url>http://weather.gov/disclaimer.html</copyright_url>
<privacy_policy_url>http://weather.gov/notice.html</privacy_policy_url>
</current_observation>
