Chart#Features

{{other uses|Chart (disambiguation)|Graph (disambiguation)|Diagram}}

File:Composition of 38th Parliament.svg showing the composition of the 38th Parliament of Canada]]

A chart (sometimes known as a graph) is a graphical representation for data visualization, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart".Cary Jensen, Loy Anderson (1992). Harvard graphics 3: the complete reference. Osborne McGraw-Hill {{ISBN|0-07-881749-8}} p.413 A chart can represent tabular numeric data, functions or some kinds of quality structure and provides different info.

The term "chart" as a graphical representation of data has multiple meanings:

A data chart is a type of diagram or graph, that organizes and represents a set of numerical or qualitative data.
Maps that are adorned with extra information (map surround) for a specific purpose are often known as charts, such as a nautical chart or aeronautical chart, typically spread over several map sheets.
Other domain-specific constructs are sometimes called charts, such as the chord chart in music notation or a record chart for album popularity.

Charts are often used to ease understanding of large quantities of data and the relationships between parts of the data. Charts can usually be read more quickly than the raw data. They are used in a wide variety of fields, and can be created by hand (often on graph paper) or by computer using a charting application. Certain types of charts are more useful for presenting a given data set than others. For example, data that presents percentages in different groups (such as "satisfied, not satisfied, unsure") are often displayed in a pie chart, but maybe more easily understood when presented in a horizontal bar chart.Howard Wainer (1997) Visual revelations: graphical tales of fate and Deception from Napoleon Bonaparte to Ross Perot, Lawrence Erlbaum Associates, Inc. {{ISBN|0-8058-3878-3}} p.87-90. On the other hand, data that represents numbers that change over a period of time (such as "annual revenue from 1990 to 2000") might be best shown as a line chart.

Features

A chart can take a large variety of forms. However, there are common features that provide the chart with its ability to extract meaning from data.

Typically the data in a chart is represented graphically since humans can infer meaning from pictures more quickly than from text. Thus, the text is generally used only to annotate the data.

One of the most important uses of text in a graph is the title. A graph's title usually appears above the main graphic and provides a succinct description of what the data in the graph refers to.

Dimensions in the data are often displayed on axes. If a horizontal and a vertical axis are used, they are usually referred to as the x-axis and y-axis. Each axis will have a scale, denoted by periodic graduations and usually accompanied by numerical or categorical indications. Each axis will typically also have a label displayed outside or beside it, briefly describing the dimension represented. If the scale is numerical, the label will often be suffixed with the unit of that scale in parentheses. For example, "Distance traveled (m)" is a typical x-axis label and would mean that the distance traveled, in units of meters, is related to the horizontal position of the data within the chart.

Within the graph, a grid of lines may appear to aid in the visual alignment of data. The grid can be enhanced by visually emphasizing the lines at regular or significant graduations. The emphasized lines are then called major gridlines, and the remainder is minor grid lines.

A chart's data can appear in all manner of formats and may include individual textual labels describing the datum associated with the indicated position in the chart. The data may appear as dots or shapes, connected or unconnected, and in any combination of colors and patterns. In addition, inferences or points of interest can be overlaid directly on the graph to further aid information extraction.

When the data appearing in a chart contains multiple variables, the chart may include a legend (also known as a key). A legend contains a list of the variables appearing in the chart and an example of their appearance. This information allows the data from each variable to be identified in the chart.

Types

{{disputed|reason=4 of the "most common charts" is totally unverified claim. Likewise the "also common" and the "less common" categorization of the various charts.|date=October 2019}}

= Common charts =

Four of the most common charts are:

File:Black cherry tree histogram.svg|Histogram

File:Försäljningsstatistik för blanddrycker.png|Bar chart

File:ActionnariatLibe2007-fr.svg|Pie chart

File:US Trade Balance from 1960.svg|Line chart

This gallery shows:

A histogram consists of tabular frequencies, shown as adjacent rectangles, erected over discrete intervals (bins), with an area equal to the frequency of the observations in the interval; first introduced by Karl Pearson.{{Cite journal| last1 = Pearson | first1 = K. |author-link=Karl Pearson| title = Contributions to the Mathematical Theory of Evolution. II. Skew Variation in Homogeneous Material| journal = Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences| volume = 186| pages = 343–414| year = 1895| doi = 10.1098/rsta.1895.0010|bibcode = 1895RSPTA.186..343P | url = https://zenodo.org/record/1432104| doi-access = free}}
A bar chart is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally. The first known bar charts are usually attributed to Nicole Oresme, Joseph Priestley, and William Playfair.{{cite web|title=First Ever Bar Charts Created in 14th Century|date=2 June 2015 |url=http://www.anychart.com/blog/2015/06/02/first-bar-chart-in-history/|publisher=AnyChart|access-date=9 February 2016}}
A pie chart shows percentage values as a slice of a pie; first introduced by William Playfair.{{cite web|url=http://www.jpowered.com/graphs-and-charts/pie-chart-history.htm|title=History of Pie Charts|publisher=JPowered|access-date=9 February 2016|archive-url=https://web.archive.org/web/20160115164419/http://jpowered.com/graphs-and-charts/pie-chart-history.htm|archive-date=15 January 2016|url-status=dead}}
A line chart is a two-dimensional scatterplot of ordered observations where the observations are connected following their order. The first known line charts are usually credited to Francis Hauksbee, Nicolaus Samuel Cruquius, Johann Heinrich Lambert and William Playfair.{{cite web|author=Michael Friendly|year=2008|url=http://www.math.yorku.ca/SCS/Gallery/milestone/milestone.pdf|title=Milestones in the history of thematic cartography, statistical graphics, and data visualization|pages=13–14|author-link=Michael Friendly}}

Other common charts are:

File:BTTFTimelines.png|Timeline chart

File:Organigram of the United States Department of the Navy.gif|Organizational chart

File:ABB.svg|Tree chart

File:Flussdiagramm (Programmablaufplan).png|Flow chart

File:MLB slugging history.svg|Area chart

File:Cartlinearlarge.png|Cartogram

File:Autosomal Dominant Pedigree Chart.svg|Pedigree chart

File:Sunburst Chart.jpg|Radial tree

= Less-common charts =

Examples of less common charts are:

File:3Variable_BubbleChart.svg|Bubble chart

File:Nightingale-mortality.jpg|Polar area diagram

File:Waterfall-chart.jpg|Waterfall chart

File:Fuentes de consumo de energía diaria 2001-2003 (FAO).svg|Radar chart

File:Heatmap incito.png|Tree map

File:LastGraph example.svg|Streamgraph

File:GapChart-Top14-2013-2014.png|GapChart

This gallery shows:

A bubble chart is a two-dimensional scatterplot where a third variable is represented by the size of the points.
A polar area diagram, sometimes called a Coxcomb chart, is an enhanced form of pie chart developed by Florence Nightingale.
A radar chart or "spider chart" or "doi" is a two-dimensional chart of three or more quantitative variables represented on axes starting from the same point.
A waterfall chart also known as a "Walk" chart, is a special type of floating-column chart.
A tree map where the areas of the rectangles correspond to values. Other dimensions can be represented with color or hue. Smaller areas go to the bottom right corner.
A streamgraph, a stacked, curvilinear area graph displaced around a central axis
A GapChart, a time series chart showing evolving gaps and equalities between series. Other dimensions can be represented with color or hue.

= Field-specific charts =

Some types of charts have specific uses in a certain field

File:Bollinger bands example, 2 stddevs.png|Open-high-low-close chart

File:Candlestick-chart.png|Candlestick chart

File:KagiSample2Chart echarts.gif|Kagi chart

File:Sparkline dowjones.svg|Sparkline

This gallery shows:

Stock market prices are often depicted with an open-high-low-close chart with a traditional bar chart of volume at the bottom.
Candlestick charts are another type of bar chart used to describe price movements of an equity over time.
A Kagi chart is a time-independent stock tracking chart that attempts to minimise noise.
Alternatively, where less detail is required, and chart size is paramount, a Sparkline may be used.

Other examples:

Interest rates, temperatures, etc., at the close of the period are plotted with a line chart.
Project planners use a Gantt chart to show the timing of tasks as they occur over time.

= Well-known named charts =

Some of the better-known named charts are:

File:Gantt przyklad 2.PNG|Gantt chart

File:Nolan-chart.svg|Nolan chart

File:5n PERT graph with critical path.svg|PERT chart

File:Smith chart bmd.gif|Smith chart

Some specific charts have become well known by effectively explaining a phenomenon or idea.

An Allele chart is a chart originating from the study of genetics to show the interaction of two data points in a grid.
A Gantt chart helps in scheduling complex projects.
The Nolan chart and the Pournelle chart classify political philosophies according to two axes of variation.
A PERT chart is often used in project management.
The Smith chart serves in radio electronics.

= Other charts =

There are dozens of other types of charts. Here are some of them:

File:ControlChart.svg|Control chart

File:GreningerChart.png|Greninger chart

File:Heatmap.png|Heatmap

File:Horoscope-Christ.jpg|Natal chart

File:TS-Wasserdampf. neu.png|Nomogram

File:800px-Pareto fr.png|Pareto chart

File:SimpleRunChart.jpg|Run chart

File:Example Strip Chart.png|Strip chart

File:Configuration System Structure Chart.jpg|Structure chart

File:Amharic vowel chart.svg|Vowel chart

One more example: Bernal chart

= Common plots =

File:Michelsonmorley-boxplot.svg|Box plot

File:Dotplot of random values 2.png|Dot plot (statistics)

File:Probability Plot.gif|Probability plot

File:oldfaithful3.png|Scatterplot

File:Spectramap Biplot Iris Flower Data Set FULL.jpg|Biplot

Chart software

While charts can be drawn by hand, computer software is often used to automatically produce a chart based on entered data. For examples of commonly used software tools, see List of charting software.

Chart#Features

Features

Types

= Common charts =

= Less-common charts =

= Field-specific charts =

= Well-known named charts =

= Other charts =

= Common plots =

Chart software

See also

References

Further reading