foreach (@lines)
{
    # Lines in the file look like:
    # Sun Jul 07 2002 10:03:03 Sensor 0 [100D973000080069] C: 25.1 F: 
+77.1
    chomp;
    my ($day, $mon, $date, $year, $time, undef, $sensor, undef, undef,
+ $c, undef, $f) = split;
    push (@{$data[0]}, $day);
    push (@{$data[$sensor + 1]}, $f);
    
    $y_max = $y_max > $f ? $y_max : $f;
    $y_min = $y_min < $f ? $y_min : $f;
}

my $y_axis_max = ceil($y_max / 10) * 10;
my $y_axis_min = floor($y_min / 10) * 10;
my $y_ticks = ($y_axis_max - $y_axis_min) / 10;

my $graph = new GD::Graph::lines();

$graph->set( 
    x_label => 'Day',
    y_label => 'Temperature (F)',
    title => $title,
    y_max_value => $y_axis_max,
    y_min_value => $y_axis_min,
    y_tick_number => 16,
    y_label_skip => 2,
    box_axis => 1,
    line_width => 3,
    y_label_position => 1,
    x_label_skip => 48,
    x_tick_offset => 48,
    x_long_ticks => 1,
    transparent => 0,
);

$graph->set_legend(@legend_labels);
$graph->plot($data);
save_chart($graph, "$img_path/$img_file");
[download]

BTW, I've since switched from using a flat file to a MySQL database, and from GD::Graph to Chart::Graph::Gnuplot. I like Chart::Graph::Gnuplot because of the amount of control Gnuplot gives over the graph. If you've ever created Gnuplot input files yourself, you'll appreciate this module. Of course, some may consider it a drawback that it relies on an external program.

my @data = (
         ["1st","2nd","3rd","4th","5th","6th","7th", "8th", "9th"],
         [    1,    2,    5,    6,    3,  1.5,    1,     3,     4],
         [ sort { $a <=> $b } (1, 2, 5, 6, 3, 1.5, 1, 3, 4) ]
);
[download]

# Create GD::Graph object
my $graph = GD::Graph->new(400, 300);

# Optionally set graph attributes
$graph->set(x_label => "X Label", y_label => "Y Label");

# Create the graph itself
my $gd = $graph->plot(\@data);

# And output the file on STDOUT (redirect to a file,
# or open a file yourself
print $gd->png;
[download]

Most of this comes from the excellent GD::Graph documentation. Read it :-)

Arjen

Yes, I read the doc, but actually *getting* to the array of array parts was the problem... The numbers were not constant so I could not manually create the array... the answer below yours was the one I was looking for, thanks. :)

----
Zak
Pluralitas non est ponenda sine neccesitate - mysql's philosphy