NAME
Chart::Manual::Types - document all supported chart types
OVERVIEW
This page illustrates all supported chart types, describes their special abilities and programming needs. More detailled information will be linked whenever available.
Generally, each chart type here is implementd by a class: Chart::* (name), which inherits most of its methods from Chart::Base.
Currently available are xycharts with points, lines, mountains, bar charts, stacked bars, error bars, pie and ring charts with split and polar coordinate systems. Also composite charts are possible.
Bars
The class Chart::Bars creates a chart made up of a series of vertical bars. The length of each bar depicts one value of your second data set. The first data set however, defines the domain. In this example the first value of the first (domain) data set is 'camel'. So the first value of the second set (30000) is positioned after the first tick on the x-axis labeled 'camel'. Right beside it is a differently colored first value of the third data set (80000). Since the option spaced_bars is set to 'true' on default both bars are not crammed together. In this example it also makes also sense to activate the horizontal y_grid lines and give them a subtle color. Further important was it to set the property min_val to zero, so that the bars could be seen in full length and not from the min value of the data sets (30000) on upwards. precision set to zero just drops the decimals on the tick label so the chart looks a little cleaner.
use Chart::Bars;
my $g = Chart::Bars->new( 600, 600 );
$g->add_dataset( qw/ camel cat dog bear shell/ );
$g->add_dataset( 30000, 40000, 80000, 50000, 90000 );
$g->add_dataset( 80000, 60000, 30000, 30000, 40000 );
$g->set(
title => 'Bars !',
x_label => 'Group',
y_label => 'Value',
y_grid_lines => 'true',
colors => {
y_grid_lines => [180, 180, 180],
},
min_val => 0,
precision => 0,
# spaced_bars => 'false',
);
$g->png("bars.png");Composite
The class Chart::Composite creates a two component chart with two types of charts which are layered one above each other. Just set the option composite info. For example, you can create a two component chart with bars and lines. A composite chart does not make sense with all combinations of chart types, but it works pretty good with Lines, Points, LinesPoints and Bars. Note that two similar chart types may come into visual conflict. Chart::Composite can do only composite charts made up of two components.
Direction
The class Chart::Direction creates a diagram based on polar coordi- nates. This type of diagram is occasionally referred to as a radial or as a radar chart. Chart::Direction plots data specified by angle (e. g., wind direction) and absolute value (e. g., wind strength). The first dataset to add is always the set of angles in degrees. The second set contains the absolute values. How additional datasets should be entered depends on the option pairs (cf. below). By default, Chart::Direction will draw a point chart. You can also get a lines chart by setting the option point to 'false' and the option line to 'true'. If you want a lines and point chart, then set both point and line to 'true'. In addition, Chart::Direction plots arrows from the center to the point or to the end of the line if the option arrow is set to 'true'.
ErrorBars
The class Chart::ErrorBars creates a point chart with error bars. This class expects the error values within the data array. By use of the add dataset() method the error values are the next two sets after the y values. The first set after the y values has to be the set of values for the upper error bounds. The next set is the array of the lower error bounds. Note that the error values are not specified absolutely but rather as offsets from the y value: the upper error values will be added to the y values, the lower error values will be subtracted. If you want to use the same value for the upper and lower error, you can set the same error option to 'true'. In this case only the set after the y values is interpreted as a set of errors. Of course, it is also possible to use the add pt() method in the appropriate way to achieve the same results.
HorizontalBars
The class Chart::HorizontalBars creates a chart of horizontally ori- ented bars.
Lines
The class Chart::Lines creates a lines chart. (If you want the data points marked with symbols, check Chart::LinesPoints on page 35.)
LinesPoints
The class Chart::LinesPoints creates a lines chart where addition- ally the individual data points are marked with a symbol. (If you want just lines without additional symbols, check Chart::Lines on page 32. If you want just symbols for the data points but no lines, check Chart::Points on page 47.)
Mountain
The class Chart::Mountain creates a mountain chart, i. e., the individ- ual data sets are stacked and the areas under the curves are colour filled. The first data set will be shown at the top of the stack, the last at the bottom.
Pareto
The class Chart::Pareto creates a Pareto chart, i. e., a set of absolute values overlaid with a line chart of the accumulated values. (This latter curve is also known as an empirical cumulative distribution function or as a Lorenz curve.) This representation usually makes sense only if the values are sorted (either in ascending or in de- scending order). Chart::Pareto plots only one data set and its labels.
Pie
The class Chart::Pie creates a pie chart. The first added set must contain the labels, the second set the values.
Points
The class Chart::Points creates a point chart (also called scatter- gram) where the individual data points are marked with a symbol. (If you want lines in addition, check Chart::LinesPoints on page 35.)
Split
The class Chart::Split creates a lines chart where both x and y axes are assumed to be numeric. Split charts are mainly intended for cases where many data points are spread over a wide x range while at the same time the y range is limited. Typical examples are weather or seismic data. The x axis will be split into several intervals of the same length (specified with the mandatory option interval). The intervals will be displayed in a stacked fashion. The start of the top interval is set with the mandatory option start. Chart::Split will draw only positive x coordinates. The y axis will not be labelled with the y values. Rather, the axis will show only the sequence numbers of the intervals.
StackedBars
The class Chart::StackedBars creates a chart made up of stacked ver- tical bars. The first data set will be shown at the bottom of the stack, the last at the top. Chart::StackedBars is a subclass of Chart::Base.
COPYRIGHT & LICENSE
Copyright 2022 David Bonner, Herbert Breunung.
This program is free software; you can redistribute it and/or modify it under same terms as Perl itself.
AUTHOR
David Bonner, <chartgrp@web.de>
Herbert Breunung, <lichtkind@cpan.org>