for my $node ($dom->findnodes('/osm/node')) {
    my $tag = $node->findnodes('tag[@k="name"]')->[0];
    print $tag,"\n";
    my $key = "$node->{lat}.$node->{lon}";
    if (exists $HoH{$key})
    {
        print "Matching key found for $key with id $HoH{$key}->{id}\n";
        # Do something useful with it here
    }
}