Chart::Manual::Types - all chart types by example
This page illustrates all supported chart types, describes their special
abilities and programming needs. Detailled information is linked whenever
possible.
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.
Generally, each chart type here is implementd by a class: Chart::* (name), which
inherits most of its methods from Chart::Base. Every constructor takes two
arguments, which are width and height of the later generated image.
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 (300) is
positioned above the first tick on the x-axis labeled 'camel'. Right beside it
is a differently colored bar, depticting the first value of the third data set
(800). Since the option spaced_bars is set to 'true' on default, both bars are
separated from the next group of bars. 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 (300)
on upwards. precision set to zero just drops the decimals on the tick label so
the chart looks a little cleaner. All the the other color set serv the same
purpose.
use Chart::Bars;
my $g = Chart::Bars->new( 500, 300 );
$g->add_dataset( qw/ camel cat dog bear shell/ );
$g->add_dataset( 300, 400, 800, 500, 900 );
$g->add_dataset( 800, 600, 300, 300, 400 );
$g->set(
title => 'Bars !',
x_label => 'Group',
y_label => 'Value',
y_grid_lines => 'true',
colors => {
y_grid_lines => 'gray70',
misc => 'gray55',
text => 'gray55',
x_label => 'gray40',
y_label => 'gray40',
title => 'gray20',
},
min_val => 0,
precision => 0,
# spaced_bars => 'false',
);
$g->png("bars.png");
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.
In this example are the data sets one and two displayed as "Bars" and
the next two als "LinesPoints" as set by the property
composite_info. Please read these sections too. Otherwise we only colored the
last data set for better contrast und cut the decimals from the axis labels
via precision.
use Chart::Composite;
my $g = Chart::Composite->new( );
$g->add_dataset( 1, 2, 3 );
$g->add_dataset( 10, 20, 30 );
$g->add_dataset( 15, 25, 32 );
$g->add_dataset( 7, 24, 23 );
$g->add_dataset( 5.1, 7.5, 9.9 );
$g->set(
title => 'Composite Chart',
composite_info => [ [ 'Bars', [ 1, 2 ] ],
[ 'LinesPoints', [ 3, 4 ] ] ],
include_zero => 'true',
precision => 0,
colors => {
dataset3 => 'darkorange',
}
);
$g->png("composite.png");
The class Chart::Direction creates a diagram based on polar coordinates. This
type of diagram is occasionally referred to as a radial or as a radar chart,
which has a circle as x-axis and its values define an angle. The y-value in
the center is min_value and the most outer circle is at max_value. In order to
reverse that you have to set polar 'true'. In our example we preferred to have
a real comparison between arrow lengths so we artificially put zero as
"min_value" by setting include_zero 'true'. The just mentioned arrow
style we achieved by deactivating point (drawing small circles) and turning on
arrow. An additional 'true' line would connect the points (arrow heads) with
lines (as well as the first and last). As in \Lines and \Points: pt_size
defines the point size and brush_size the line thickness. Usually the
background of each chart (just inside the coordinate system) is a light gray -
here deactivated. Radial grid lines are drawn every 45 degrees
(angle_interval).
As with most chart types, the first data set defines the domain : the x-values
of all following data sets, which then define the associated y-values (and
therefore all sets have to have the same length). Because we set in this
example pairs 'true', now every odd numbered data set is the domain for the
next set. But they still all sets have to have the same length.
use Chart::Direction;
my $g = Chart::Direction->new( 500, 500 );
$g->add_dataset( 210, 220, 200, 215, 225, 200 );
$g->add_dataset( 30, 40, 20, 35, 45, 20 );
$g->add_dataset( 30, 40, 20, 35, 45, 20 );
$g->add_dataset( 30, 40, 20, 35, 45, 20 );
$g->add_dataset( 120, 130, 110, 125, 135, 110 );
$g->add_dataset( 30, 40, 20, 35, 45, 20 );
$g->add_dataset( 300, 310, 290, 305, 315, 290 );
$g->add_dataset( 30, 40, 20, 35, 45, 20 );
$g->set(
title => 'Direction Demo',
angle_interval => 45,
precision => 0,
arrow => 'true',
point => 'false',
include_zero => 'true',
legend => 'none',
grey_background => 'false',
pairs => 'true',
);
$g->png("direction.png");
The class Chart::ErrorBars creates a point chart with error bars, which are
vertical lines, depicting the uncertainty - a range which is possible for that
value. As seen in the example, we need four data sets to define a series of
error bars. The first data set are the x-values of the error bars, the second
the y-values. The third set holds the lenght of the upper part of the error
bar and the fourth set the lower part (distance between main point and the
lower bound of the error bar). The fourth set might be omitted, when property
same_error is set 'true'. In this case upper and lower part of the error bar
have the same size. Because all this produced only one set of error bars with
one color, there is no need for a legend. That is why it is switched off by
setting property legend to 'none'. The label on the x-axis are painted in the
'staggered' style, so they don't overlap. pt_size refers to the diameter in
pixel of the errors bars central point. brush_size is the thickness of the
bar. For better readability 'both' y_axes were labeled.
use Chart::ErrorBars;
my $g = Chart::ErrorBars->new( 500, 400 );
$g->add_dataset(qw(1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5));
$g->add_dataset(qw(1 1.1 1.2 1.1 1.14 1.15 1.26 1.2 1.1 1.19 1.2 1.4 1.6 2.0 2.5 3.1));
$g->add_dataset(qw(0.4 0.1 0.2 0.1 0.14 0.15 0.26 0.27 0.1 0.19 0.2 0.1 0.1 0.2 0.1 0.3));
$g->add_dataset(qw(0.2 0.11 0.12 0.11 0.2 0.3 0.12 0.27 0.11 0.3 0.2 0.2 0.2 0.1 0.1 0.2));
$g->set(
title => 'Error Bars Demo',
legend => 'none',
y_axes => 'both',
x_ticks => 'staggered',
pt_size => 12,
brush_size => 2,
grid_lines => 'true',
colors => {
grid_lines => 'gray70',
misc => 'gray65',
},
);
$g->png("error.png");
The class Chart::HorizontalBars creates a chart of horizontally oriented bars.
Same rules apply as in "Bars", except due negative values in our
data sets here min_val doesn't have to be set to zero. And instead of
y_grid_lines we activate and color x_grid_lines. Deactivating the grey
background of the plot just adds a little friendliness.
use Chart::HorizontalBars;
my $g = Chart::HorizontalBars->new( 600, 600 );
$g->add_dataset( qw/ camel cat dog bear shell/ );
$g->add_dataset( -300, 400, 800, -500, 200 );
$g->add_dataset( 800, -600, 300, 300, 400 );
$g->set(
title => 'Bars !',
x_label => 'Group',
y_label => 'Value',
x_grid_lines => 'true',
precision => 0,
colors => {
x_grid_lines => 'gray70',
misc => 'gray55',
text => 'gray55',
x_label => 'gray40',
y_label => 'gray40',
title => 'gray20',
}
grey_background => 'false',
);
$g->png("hbars.png");
The class Chart::Lines creates a chart with lines that connect the would be data
points. If you want to make the points more visible, use
"LinesPoints". The only special property is brush_size, the
thickness of the lines, which was not even utilized in this example. To make
things nicer we put only some softer colors to the horizontal (y) grid lines
and the box and ticks (misc) and placed the legend on the bottom so that the
chart doesn't get sqeezed by it.
use Chart::Lines;
my $g = Chart::Lines->new( 600, 400 );
$g->add_dataset( 'foo', 'bar', 'whee', 'ding', 'bat', 'bit' );
$g->add_dataset( 3.2, 4.34, 9.456, 10.459, 11.24234, 14.0234 );
$g->add_dataset( -1.3, 8.4, 5.34, 3.234, 4.33, 13.09 );
$g->add_dataset( 5, 7, 2, 10, 12, 2.3445 );
$g->set(
title => 'Lines Chart',
legend => 'bottom' ,
y_label => 'y label 1',
precision => 0,
y_grid_lines => 'true',
colors => {
y_label => 'orangepeel',
y_grid_lines => [ 190, 190, 190 ],
misc => [ 100, 100, 100 ],
},
);
$g->png("lines.png");
The class Chart::LinesPoints creates chart, which is a combination of
"Points" and "Lines": shaped symbols connected by lines.
This requires a combination of the special properties of both chart types:
brushStyle (point shape), pt_size (point diameter) and brush_size (line
thickness).
In our example we named both axis via x_label and y_label and set xy_plot off,
which is not really needed, since it is on 'false' per default. This allows
you to give the x-axis none numerical, custom tick labels, which are by
accident the numbers 1 .. 17, as the first data row shows. The purpose of this
maneuver is to not have zero as the first column label.
Because the origin of coordinate system is usually in the left lower corner, we
used a trick to flip the y-axis having the smallest values up. We negated all
values in the data, so that 8 is lower than 2, because -8 is smaller than -2.
Than we transformed the y-axis labels with a function, that negates the value
of the original label, erasing the minus sign.
For additional clarity, we put the names of the teams into the legend, which is
per default on the right side. And to make the code more compact, we packed
the first (just labels) and the four real data sets (rows) together into an
array or arrays and gave it as second argument directly to the drawing method.
use Chart::LinesPoints;
my $g = Chart::LinesPoints->new( 600, 300 );
$g->set(
title => 'Soccer Season 2002',
legend_labels => ['NY Soccer Club', 'Denver Tigers',
'Houston Spacecats', 'Washington Presidents'],
y_label => 'position in the table',
x_label => 'day of play',
grid_lines => 'true',
f_y_tick => sub { - $_[0] },
# xy_plot => 'true',
integer_ticks_only => 'true',
colors => {
grid_lines => 'gray70',
},
);
$g->png("linespoints.png", [
[qw(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17)],
[qw(-7 -5 -6 -8 -9 -7 -5 -4 -3 -2 -4 -6 -3 -5 -3 -4 -6)],
[qw(-1 -1 -1 -1 -2 -2 -3 -3 -4 -4 -6 -3 -2 -2 -2 -1 -1)],
[qw(-4 -4 -3 -2 -1 -1 -1 -2 -1 -1 -3 -2 -4 -3 -4 -2 -2)],
[qw(-6 -3 -2 -3 -3 -3 -2 -1 -2 -3 -1 -1 -1 -1 -1 -3 -3)],
]);
The class Chart::Mountain creates a mountain chart, which is a line chart (see
"Lines"), where the area under the curve, right to the curve below
is filled with the color of the data set. In the following example we use
custom colors in hex notation (as supported by Chart::Color) which are getting
mapped onto the colors settings of dataset0 .. dataset4. As always, the first
data set (row in the data table) holds the domain or x-axis labels. Another
specialty of mountain charts are patterns (not provided !), to fill the area
with. We load them via GD and give them over to the 'patterns' property.
Patterns are small images with one color and the second being transparent.
use Chart::Mountain;
my @data = (
["1st", "2nd", "3rd", "4th", "5th", "6th", "7th", "8th", "9th" ],
[ 3, 7, 8, 2, 4 , 8.5, 2, 5, 9],
[ 4, 2, 5, 6, 3 , 2.5, 3, 3, 4],
[ 7, 3, 2, 8, 8.5, 2 , 9, 4, 5],
);
my @hex_colors = ('#0099FF', '#00CC00', '#EEAA00', '#FF0099','#3333FF');
my $PNG;
my @patterns = map {
open( $PNG, '<', "./patterns/PATTERN$_.PNG" ) or die "Can't load pattern $_";
GD::Image->newFromPng( $PNG );
} 0 .. 4;
my $g = new Chart::Mountain( 500, 300);
$g->set(
title => 'Mountain Chart with Patterns',
x_label => 'Lengths',
y_label => 'Height',
grid_lines => 'true',
patterns => \@patterns,
precision => 1,
colors => {
grid_lines => 'gray70',
misc => 'gray55',
map { ( "dataset$_" => $hex_colors[$_] ) } 0 .. $#hex_colors,
},
);
$g->png( 'mountain.png', \@data );
The class Chart::Pareto creates a combination of a "Bars" and a
"Lines" chart. The bars display absolute values of the data set
(Pareto accepts only one), while the line represent the accumulation (sum of
all values from the start on the left up to this value). For a better
orientation the absolute values should be sorted. In case your data set is not
already, change the property sort to 'true'. (Note that the days of the week
are not in chronological order, but in the order of decreasing sale amounts.)
The first given data set is like in most cases the domain (x-axis labels). So
the color of the first data set containing numbers has the color of dataset0
and the accumulation gets the color of dataset1 (which are per default also
red and green, but in reverse order). We choose a Pantone Report designer red,
which sticks out but is not too shrill.
For better optics we set spaced_bars off, so that the bars touch each other and
give a nice counterweight to the red color of the line. It's also a bit nicer,
when the red labels above the red line don't stick out the chart, so we
increased the max_val from 5180 to 5500. Finally to prevent the y-axis from
overcrowding, we set labels (and y_grid_lines) only every 250 by setting
skip_int_ticks and activating integer_ticks_only.
use Chart::Pareto;
my $g = Chart::Pareto->new( 450, 400 );
$g->add_dataset( 'Mo', 'Tue', 'We', 'Th', 'Fr', 'Sa', 'Su' );
$g->add_dataset( 2500, 1000, 250, 700, 100, 610, 20 );
$g->set(
title => 'Sold Tickets for Beethovens 9th',
y_label => 'Sold Tickets',
x_label => '! sold out in the first week !',
sort => 'true',
max_val => 5500,
integer_ticks_only => 'true',
skip_int_ticks => 250,
y_grid_lines => 'true',
spaced_bars => 'false',
legend => 'none',
colors => {
title => 'darkblue',
dataset0 => 'green',
dataset1 => 'aurorared',
x_label => 'aurorared',
y_grid_lines => 'white',
},
);
$g->png("pareto.png");
The class Chart::Pie creates a pie or ring chart. The first added data set must
contain the labels and the second set the values. Our example displays a ring
chart with a thickness of 35% (of the radius). If the ring property is
omitted, the chart form falls back to regular pie. Every ring slice is labeled
with the stated label, plus the percentage of its value, as defined with the
property label_values. Connecting lines between label and slice are drawn
because legend_lines is set to 'true'. The actual legend is placed on the
bottom, in order to leave the ring as large as possible. The legend again
shows the association between color and data point and its value because
legend_label_values is set to 'values'. Unlike other chart types, where one
data set is correlated with a color, here every slice has to have its own
color. Thats why the first data point has the color of dataset0 the second of
dataset1 and so forth. In most cases the default colors are good enough,
unless you have special meanings in mind. Please also note the multi line
(row) title text.
use Chart::Pie;
my $g = Chart::Pie->new( 500, 450 );
$g->add_dataset( qw/eins zwei drei vier fuenf sechs sieben acht neun zehn/ );
$g->add_dataset( 120, 50, 100, 80, 40, 45, 150, 60, 110, 50 );
$g->set( 'title' => 'Pie\nDemo Chart',
'legend' => 'bottom',
'legend_label_values' => 'value',
'label_values' => 'percent',
'legend_lines' => 'true',
'ring' => 0.35,
);
$g->png("pie.png");
The class Chart::Points creates a xy-chart (also called scattergram), where the
individual data points are marked with a symbol. The shape of the symbol is
selected by the property brushStyle, which was not utilized in this example,
in order to use the default shape: a circle of a diameter set by pt_size. All
shapes can be seen in the demo above, right. (If you want in addition lines,
connecting the points, check "LinesPoints".)
The first data set comprises the domain set, displayed on the x-axis. precision
set to zero cuts the decimals on the y-axis labels and keeps it clean. The
method "add_pt" appends to every data set another value, adding
another column to the chart. png_border does just adds frame of 10 pixel width
around the entire image. They middle gray grid lines are just easy for the
eyes.
use Chart::Points;
my $g = Chart::Points->new();
$g->add_dataset( 'foo', 'bar', 'blank' );
$g->add_dataset( 3, 4, 9 );
$g->add_dataset( 8, 6, 0 );
$g->add_dataset( 5, 7, 2 );
$g->add_pt( 'dat', 1, 5, 7 );
$g->set(
title => 'Points Chart',
pt_size => 18,
# brushStyle => 'Star',
precision => 0,
grid_lines => 'true',
png_border => 10,
colors => {
grid_lines => 'gray70',
},
);
$g->png("points.png");
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 and starting at 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.
use Chart::Split;
my $g = Chart::Split->new( 500, 500 );
my @domain = 1 .. 4000;
my @rnd = map { srand( time() / $_ * 50 ); rand(10) } @domain, 4001;
my @diff = map { abs $rnd[$_-1] - $rnd[$_] } @domain;
pop @rnd;
$g->add_dataset(@domain);
$g->add_dataset(@rnd);
$g->add_dataset(@diff);
$g->set(
title => "Random Numbers Test",
x_label => "4000 Random Numbers",
start => 0,
interval => 400,
brush_size => 1,
interval_ticks => 0,
legend => 'bottom',
legend_labels => ['random numbers', 'difference' ],
colors => {
title => 'darkblue',
text => 'gray45',
misc => 'gray45',
},
);
$g->png("split.png");
The class Chart::StackedBars is a variant of "Bars" that stacks bars
belonging to one x-value on top of each other, instead of putting them beside
each other. Data sets 0..n are ordered from the bottom up. They are in most
cases more intuitive than "Pie" charts, because its easier to intuit
linear than quadratic ratios. As in the Bars example we activated horizontal
grid lines, which were subtle colored. To surpress decimals on the y-axis
precision was turned down. And as in most cases - the first data set is the
domain, which will be drawn as x-axis labels.
use Chart::StackedBars;
my $g = Chart::StackedBars->new( 600, 400 );
$g->add_dataset( 'camel', 'dromedar', 'llama', 'vicuna');
$g->add_dataset( 3, 4, 9, 10, );
$g->add_dataset( 8, 6, 1, 12, );
$g->add_dataset( 5, 7, 2, 13, );
$g->set(
title => 'Stacked Bars',
legend => 'left',
precision => 0,
y_grid_lines => 'true',
grey_background => 'false',
colors => {
grid_lines => 'gray80',
misc => 'gray55',
text => 'gray55',
x_label => 'gray40',
y_label => 'gray40',
title => 'gray20',
}
);
$g->png("stackedbars.png");
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.
David Bonner,
Herbert Breunung, <
[email protected]>