Change the value of a text node using SimpleXML

Question

I am trying to write a code where it will find a specific element in my XML file and then change the value of the text node. The XML file has different namespaces. Till now, I have managed to register the namespaces and also echo the text node of the element, which I want to change.

   <?php

   $xml = simplexml_load_file('getobs.xml');

   $xml->registerXPathNamespace('g','http://www.opengis.net/gml');

   $result = $xml->xpath('//g:beginPosition');


   foreach ($result as $title) {
   echo $title . "\n";
   }
   ?>

My question is: How can I change the value of this element using SimpleXML? I tried to use the nodeValue command but I am not able to make it work.

This is a part of the XML:

        <sos:GetObservation xmlns:sos="http://www.opengis.net/sos/1.0"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" service="SOS" version="1.0.0"  srsName="urn:ogc:def:crs:EPSG:4326">
          <sos:offering>urn:gfz:cawa:def:offering:meteorology</sos:offering>
            <sos:eventTime>
              <ogc:TM_During xmlns:ogc="http://www.opengis.net/ogc" xsi:type="ogc:BinaryTemporalOpType">
              <ogc:PropertyName>urn:ogc:data:time:iso8601</ogc:PropertyName>
                <gml:TimePeriod xmlns:gml="http://www.opengis.net/gml">
                  <gml:beginPosition>2011-02-10T01:10:00.000</gml:beginPosition>

Thanks Dimitris

Answer 1

In the end I managed to do it by using the PHP XML DOM. Here is the code that I used in order to change the text node of a specific element:

  <?php
  // create new DOM document and load the data
  $dom = new DOMDocument;
  $dom->load('getobs.xml');
  //var_dump($dom);
  // Create new xpath and register the namespace
  $xpath = new DOMXPath($dom);
  $xpath->registerNamespace('g','http://www.opengis.net/gml');
  // query the result amd change the value to the new date
  $result = $xpath->query("//g:beginPosition");
  $result->item(0)->nodeValue = 'sds';
  // save the values in a new xml
  file_put_contents('test.xml',$dom->saveXML());
  ?>

Answer 2

Not wanting to switch from the code I've already made for SimpleXML, I found this solution:

http://www.dotdragnet.com/forum/index.php?topic=3979.0

Specificially:

$numvotes = $xml->xpath('/gallery/image[path="'.$_GET["image"].'"]/numvotes');
...
$numvotes[0][0] = $votes;

Hope this helps!