Chart::Plot 0.11

Chart::Plot is a Perl module to plot two dimensional data in an image.

SYNOPSIS

use Chart::Plot;

my $img = Chart::Plot->new();
my $anotherImg = Chart::Plot->new ($image_width, $image_height);

$img->setData (@dataset) or die( $img->error() );
$img->setData (@xdataset, @ydataset);
$img->setData (@anotherdataset, red_dashedline_points);
$img->setData (@xanotherdataset, @yanotherdataset,
Blue SolidLine NoPoints);

my ($xmin, $ymin, $xmax, $ymax) = $img->getBounds();

$img->setGraphOptions (horGraphOffset => 75,
vertGraphOffset => 100,
title => My Graph Title,
horAxisLabel => my X label,
vertAxisLabel => my Y label );

print $img->draw();

I wrote Chart::Plot to create images of some simple graphs of two dimensional data. The other graphing interface modules to GD.pm I saw on CPAN either could not handle negative data, or could only chart evenly spaced horizontal data. (If you have evenly spaced or nonmetric horizontal data and you want a bar or pie chart, I have successfully used the GIFgraph and Chart::* modules, available on CPAN.)

Chart::Plot will plot multiple data sets in the same graph, each with some negative or positive values in the independent or dependent variables. Each dataset can be a scatter graph (data are represented by graph points only) or with lines connecting successive data points, or both. Colors and dashed lines are supported, as is scientific notation (1.7E10). Axes are scaled and positioned automatically and 5-10 ticks are drawn and labeled on each axis.

You must have already installed the GD.pm library by Lincoln Stein, available on CPAN or at http://stein.cshl.org/WWW/software/GD/ Versions of GD below 1.19 supported only gif image format. Versions between 1.20 and 1.26 support only png format. GD version 1.27 supports either png or jpg image formats. Chart::Plot will draw whichever format your version of GD will draw. (See below for a method to determine which format your version supports.)