steve: updated alt atribute content for the webcam example to include info about unchanging aspects of the image

steve: updated alt atribute content for the webcam example to include
info about unchanging aspects of the image

http://dev.w3.org/cvsweb/html5/alt-techniques/Overview.html?r1=1.15&r2=1.16&f=h

===================================================================
RCS file: /sources/public/html5/alt-techniques/Overview.html,v
retrieving revision 1.15
retrieving revision 1.16
diff -u -d -r1.15 -r1.16
--- Overview.html 21 Apr 2010 10:44:56 -0000 1.15
+++ Overview.html 21 Apr 2010 16:24:24 -0000 1.16
@@ -902,18 +902,44 @@
 <h3 id="webcam">10. Webcam images</h3>
 <p>Webcam images are static images that are automatically updated periodically. Typically the images are from a fixed viewpoint, the images may update on the page automatically as each new image is uploaded from the camera or the user may be required to refresh the page to view an updated image. Examples include  traffic and weather cameras.</p>
 <h4>Example 10.1</h4>
-<p>Context: A webcam image updated every hour, with a viewpoint from the top of Sopwith house, looking north.</p>
+<p>This example is fairly typical; the title and a time stamp are included in the image, automatically generated by the webcam software. It would be better if the text information was not included in the image, but as it is part of the image, it is required that it is provided as a text alternative. A caption is also provided using the <code>figure</code> and <code>figcaption</code> elements.  As the image is provided to give a visual indication of the current weather near Sopwith House, a link to a local weather forecast is provided, as with automatically generated and uploaded webcam images it is impractical to provide such information as a text alternative. The text of the alt attribute is a prose version of the timestamp, designed to make the text more understandable when announced by text to speech software.</p>
+<p><strong>Note: </strong><code>aria-describedby</code> is used to explicitly associate the caption with the image as the <code>figure</code> and <code>figcaption</code> elements are not currently supported.</p>
+<p>Context: A webcam image updated every hour, with a viewpoint from the top of Sopwith House, looking north.</p>
 <div class="example">
   <p><strong>Image example in context:</strong></p>
   <div class="element1">
     
-    <p><img src="images/webcam1.jpg" alt="Sopwith house weather cam. Taken on the 21/04/10 at 11:51 and 34 seconds." width="296" height="225"></p>
+    <p><img src="images/webcam1.jpg" alt="Sopwith house weather cam. Taken on the 21/04/10 at 11:51 and 34 seconds. 
+In the foreground are the safety rails on the flat part of the roof. Nearby ther are low rise industrial buildings, beyond those are block of flats. 
+In the distance there's a church steeple." width="296" height="225"></p>
     <p>View from the top of Sopwith house, looking towards North Kingston.</p>
     <p>This image is updated every hour.</p>
     <p>View the  <a href="http://news.bbc.co.uk/weather/forecast/4296?area=Kingston">latest weather details</a> for Kingston upon Thames.</p>
   </div>
   <p><strong>Code Example:</strong></p>
   <pre>&lt;figure&gt;   
+&lt;img src="webcam1.jpg" <strong>alt="Sopwith house weather cam. Taken on the 21/04/10 at 11:51 and 34 seconds. 
+In the foreground are the safety rails on the flat part of the roof. Nearby ther are low rise industrial buildings, beyond those are block of flats. 
+In the distance there's a church steeple."</strong> aria-describedby=&quot;s1&quot;&gt;  
+&lt;figcaption id=&quot;s1&quot;&gt;View from the top of Sopwith house, looking towards north Kingston.&lt;/figcaption&gt;
+&lt;p&gt;This image is updated every hour.&lt;/p&gt;
+&lt;p&gt;View the &lt;a href=&quot;http://news.bbc.co.uk/weather/forecast/4296?area=Kingston&quot;&gt;
+latest weather details&lt;/a&gt; for Kingston upon Thames.&lt;/p&gt;   
+&lt;/figure&gt;  </pre>
+</div>
+<h4>Example 10.2</h4>
+<p class="note">to do</p>
+<p>Context: A webcam image updated every hour, with a viewpoint from the top of Sopwith house, looking north.</p>
+<div class="example">
+  <p><strong>Image example in context:</strong></p>
+  <div class="element1">
+    <p><img src="images/webcam1.jpg" alt="Sopwith house weather cam. Taken on the 21/04/10 at 11:51 and 34 seconds." width="296" height="225"></p>
+    <p>View from the top of Sopwith house, looking towards North Kingston.</p>
+    <p>This image is updated every hour.</p>
+    <p>View the <a href="http://news.bbc.co.uk/weather/forecast/4296?area=Kingston">latest weather details</a> for Kingston upon Thames.</p>
+  </div>
+  <p><strong>Code Example:</strong></p>
+  <pre>&lt;figure&gt;   
 &lt;img src="webcam1.jpg" <strong>alt="Sopwith house weather cam. Taken on the 21/04/10 at 11:51 and 34 seconds."</strong> aria-describedby=&quot;s1&quot;&gt;  
 &lt;figcaption id=&quot;s1&quot;&gt;View from the top of Sopwith house, looking towards north Kingston.&lt;/figcaption&gt;
 &lt;p&gt;This image is updated every hour.&lt;/p&gt;

Received on Wednesday, 21 April 2010 16:25:16 UTC