rss feed handling

If you look at the feed from the USGS on Mag 5+ earthquakes over the
past week at:

  < http://earthquake.usgs.gov/earthquakes/catalogs/eqs7day-M7.xml >

You will see these sorts of things in each entry:

      <item>
      <pubDate>Sun, 06 Nov 2011 03:53:10 GMT</pubDate>
      <title>M 5.2, Oklahoma</title>
      <description>November 06, 2011 03:53:10 GMT</description>
      <link>http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usb0006klz.php</link>
      <geo:lat>35.5993</geo:lat>
      <geo:long>-96.7515</geo:long>
      <dc:subject>5</dc:subject>
      <dc:subject>pasthour</dc:subject>
      <dc:subject>5.00 km</dc:subject>
      <guid isPermaLink="false">usb0006klz</guid>
      </item>

The pubDate, title, description, link and guid tags are all part of
the RSS standard. The geo: and dc: tags are not, and are specified in
the opening rss tag:

     <rss version="2.0"
     xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#"
     xmlns:dc="http://purl.org/dc/elements/1.1/">

by those xmlns attributes. So, unless you're lucky, almost any canned
solution for dealing with RSS might not work with any particular feed.

The best solution I've come up with just using SimpleXML (or one of
it's derivatives). Here's a quickie I wrote to test out the above
link:

	$feed_raw = file_get_contents("http://earthquake.usgs.gov/earthquakes/catalogs/eqs1day-M2.5.xml");
	$feed = new SimpleXMLElement($feed_raw);
	$feed->registerXPathNamespace('geo','http://www.w3.org/2003/01/geo/wgs84_pos#');
	$feed->registerXPathNamespace('dc','http://purl.org/dc/elements/1.1/');

	echo "<pre>";
	print_r($feed->getNamespaces(TRUE));
	print_r($feed->getDocNamespaces(TRUE));
	echo "</pre>";