It's not clear what you want the output to be, but my guess would be you are
looking for something like

<xsl:value-of select="Data[@name='grid_ref']/value"/> 

Michael Kay
http://www.saxonica.com/

> -----Original Message-----
> From: Alan Hale [mailto:alan.hale@xxxxxxxxxxx] 
> Sent: 17 March 2009 21:43
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject:  ExtendedData from KML
> 
> Hi
> 
> I am attempting to convert a KML file to CSV using XSLT. I 
> can succeed with most elements and attributes, along these lines:
> 
>     <xsl:template match="Folder">
>          <xsl:for-each select="Placemark">
>             <xsl:value-of select="@id" />,
>             <xsl:value-of select="name" />,
>             <xsl:value-of select="Point/coordinates" />,
>             <xsl:value-of select="Snippet" />
>             <br />
>         </xsl:for-each>
>     </xsl:template>
> 
> but I don't know how to deal with the ExtendedData section 
> which has multiple <Data> elements identifed with individual 
> attributes, e.g.:
> 
>  <ExtendedData>
>           <Data name="sciencName">
>             <value>Acer campestre</value>
>           </Data>
>           <Data name="grid_ref">
>             <value>SN593798</value>
>           </Data>
>           <Data name="eng_name">
>             <value>Field Maple</value>
>           </Data>
>           <Data name="rdb_status">
>             <value>Lower risk - least concern</value>
>           </Data>
> </ExtendedData>
> 
> Any advice much appreciated.
> 
> Thanks
> 
> Alan Hale
> Aberystwyth