XSLT functions for distance conversions

Here are two simple XSLT functions for converting between miles and km

 <xsl:function name="fn:miles-to-km">
  <xsl:param name="miles" as="xs:decimal"/> 
  <xsl:sequence select="format-number($miles * 1.609347, '0.0')"/>
 </xsl:function>
 
 <xsl:function name="fn:km-to-miles">
  <xsl:param name="km" as="xs:decimal"/> 
  <xsl:sequence select="format-number($km * 0.621371, '0.0')"/>
 </xsl:function>