decimal2dms.pl

sub decimal2dms {
    my ($decimal) = @_;

    my $sign = $decimal <=> 0;
    my $degrees = int($decimal);

    # convert decimal part to minutes
    my $dec_min = abs($decimal - $degrees) * 60;
    my $minutes = int($dec_min);
    my $seconds = ($dec_min - $minutes) * 60;

    return ($degrees, $minutes, $seconds, $sign);
}

dms2decimal.pl

sub dms2decimal {
    my ($degrees, $minutes, $seconds) = @_;
    my $decimal;

    if ($degrees >= 0) {
        $decimal = $degrees + $minutes/60 + $seconds/3600;
    } else {
        $decimal = $degrees - $minutes/60 - $seconds/3600;
    }

    return $decimal;
}