Route is as follows:

% foreach my $i (0..$#islandids) {
%   my $islandid= $islandids[$i];
%   my $archipelago= $archipelagoes[$i];
%   $islandid= '' unless defined $islandid;
%   $archipelago= '' unless defined $archipelago;
%
  islandid=<% $islandid |h %>  archipelago=<% $archipelago |h %>
%
% }