XSL transformation - Namespace prefix undeclared

Question

I have an XSL file by which I would like to convert an XML file. This XML file has been obtained renaming the original file which had .safe extension. here you can see its f

Answer 1

You must include

xmlns:safe="http://www.esa.int/safe/sentinel-1.0"

in your xslt, best at top level:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
    xmlns:safe="http://www.esa.int/safe/sentinel-1.0" ...