Chart

# Chart

Discussion

Encyclopedia
A chart is a graphical representation of data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

, in which "the data is represented by symbol
Symbol
A symbol is something which represents an idea, a physical entity or a process but is distinct from it. The purpose of a symbol is to communicate meaning. For example, a red octagon may be a symbol for "STOP". On a map, a picture of a tent might represent a campsite. Numerals are symbols for...

s, such as bars in a bar chart
Bar chart
A bar chart or bar graph is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally....

, lines in a line chart
Line chart
A line chart or line graph is a type of graph, which displays information as a series of data points connected by straight line segments. It is a basic type of chart common in many fields. It is an extension of a scatter graph, and is created by connecting a series of points that represent...

, or slices in a pie chart
Pie chart
A pie chart is a circular chart divided into sectors, illustrating proportion. In a pie chart, the arc length of each sector , is proportional to the quantity it represents. When angles are measured with 1 turn as unit then a number of percent is identified with the same number of centiturns...

". A chart can represent tabular
Table (information)
A table is a means of arranging data in rows and columns.Production % of goalNorth 4087102%South 4093110% The use of tables is pervasive throughout all communication, research and data analysis. Tables appear in print media, handwritten notes, computer software, architectural...

numeric
Number
A number is a mathematical object used to count and measure. In mathematics, the definition of number has been extended over the years to include such numbers as zero, negative numbers, rational numbers, irrational numbers, and complex numbers....

data, functions
Graph of a function
In mathematics, the graph of a function f is the collection of all ordered pairs . In particular, if x is a real number, graph means the graphical representation of this collection, in the form of a curve on a Cartesian plane, together with Cartesian axes, etc. Graphing on a Cartesian plane is...

or some kinds of qualitative structures.

The term "chart" as a graphical representation of data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

has multiple meanings:
• A data chart is a type of diagram
Diagram
A diagram is a two-dimensional geometric symbolic representation of information according to some visualization technique. Sometimes, the technique uses a three-dimensional visualization which is then projected onto the two-dimensional surface...

or graph
Graphics
Graphics are visual presentations on some surface, such as a wall, canvas, computer screen, paper, or stone to brand, inform, illustrate, or entertain. Examples are photographs, drawings, Line Art, graphs, diagrams, typography, numbers, symbols, geometric designs, maps, engineering drawings,or...

, that organizes and represents a set of numerical or qualitative data.
• Map
Map
A map is a visual representation of an area—a symbolic depiction highlighting relationships between elements of that space such as objects, regions, and themes....

s that are adorned with extra information for some specific purpose are often known as charts, such as a nautical chart
Nautical chart
A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land , natural features of the seabed, details of the coastline, navigational hazards, locations of natural and man-made aids...

or aeronautical chart
Aeronautical chart
An aeronautical chart is a map designed to assist in navigation of aircraft, much as nautical charts do for watercraft, or a roadmap for drivers...

.
• Other domain specific constructs are sometimes called charts, such as the chord chart
Chord chart
A chord chart is a form of musical notation that in addition to writing out non-embellished melody, describes harmonic and rhythmic information. It is the most common form of notation used by professional session musicians playing jazz or popular music. It is intended primarily for a rhythm section...

in music notation or a record chart
Record chart
A record chart is a ranking of recorded music according to popularity during a given period of time. Examples of music charts are the Hit parade, Hot 100 or Top 40....

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 that they are produced from. They are used in a wide variety of fields, and can be created by hand (often on graph paper
Graph paper
Graph paper, graphing paper, grid paper or millimeter paper is writing paper that is printed with fine lines making up a regular grid. The lines are often used as guides for plotting mathematical functions or experimental data and drawing diagrams. It is commonly found in mathematics and...

) or by computer using a charting application
Charting application
A charting application is a computer program that is used to graphically create a graphical representation based on some non-graphical data that is entered by a user, most often through a spreadsheet application, but also through a dedicated specific scientific application , or...

. Certain types of charts are more useful for presenting a given data set than others. For example, data that presents percentage
Percentage
In mathematics, a percentage is a way of expressing a number as a fraction of 100 . It is often denoted using the percent sign, “%”, or the abbreviation “pct”. For example, 45% is equal to 45/100, or 0.45.Percentages are used to express how large/small one quantity is, relative to another quantity...

s in different groups (such as "satisfied, not satisfied, unsure") are often displayed in a pie chart
Pie chart
A pie chart is a circular chart divided into sectors, illustrating proportion. In a pie chart, the arc length of each sector , is proportional to the quantity it represents. When angles are measured with 1 turn as unit then a number of percent is identified with the same number of centiturns...

, but may be more easily understood when presented in a horizontal bar chart
Bar chart
A bar chart or bar graph is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally....

. 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
Line chart
A line chart or line graph is a type of graph, which displays information as a series of data points connected by straight line segments. It is a basic type of chart common in many fields. It is an extension of a scatter graph, and is created by connecting a series of points that represent...

.

## Features of a chart

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

Typically a chart is graphical, containing very little text, since humans are generally able to infer meaning from pictures quicker than from text. One of the more important uses of text in a graph is in 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 respectively. 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 travelled in metres is related to the horizontal position of the data.

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 grid lines and the rest of the grid lines are minor grid lines.

The data of a chart can appear in all manner of formats, with or without individual labels. It may appear as dots or shapes, connected or unconnected, and in any combination of colors and patterns. Inferences or points of interest can be overlayed 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. 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. by: Jemimah

### Common charts

Four of the most common charts are:
This gallery shows:
• A histogram
Histogram
In statistics, a histogram is a graphical representation showing a visual impression of the distribution of data. It is an estimate of the probability distribution of a continuous variable and was first introduced by Karl Pearson...

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.
• A bar chart
Bar chart
A bar chart or bar graph is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally....

is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally.
• A pie chart
Pie chart
A pie chart is a circular chart divided into sectors, illustrating proportion. In a pie chart, the arc length of each sector , is proportional to the quantity it represents. When angles are measured with 1 turn as unit then a number of percent is identified with the same number of centiturns...

shows percentage values as a slice of a pie.
• A line chart
Line chart
A line chart or line graph is a type of graph, which displays information as a series of data points connected by straight line segments. It is a basic type of chart common in many fields. It is an extension of a scatter graph, and is created by connecting a series of points that represent...

is a two-dimensional scatterplot of ordered observations where the observations are connected following their order.

Other common charts are:

### Less-common charts

Examples of less common charts are:
This gallery shows:
• A bubble chart
Bubble chart
A bubble chart is a type of chart where each plotted entity is defined in terms of three distinct numeric parameters. Bubble charts can facilitate the understanding of the social, economical, medical, and other scientific relationships.- Overview :...

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 developed by Florence Nightingale
Florence Nightingale
Florence Nightingale OM, RRC was a celebrated English nurse, writer and statistician. She came to prominence for her pioneering work in nursing during the Crimean War, where she tended to wounded soldiers. She was dubbed "The Lady with the Lamp" after her habit of making rounds at night...

is an enhanced form of pie chart.
A radar chart is a graphical method of displaying multivariate data in the form of a two-dimensional chart of three or more quantitative variables represented on axes starting from the same point...

or "spider chart" is a two-dimensional chart of three or more quantitative variables represented on axes starting from the same point.
• A waterfall chart
Waterfall chart
Waterfall Chart is a form of data visualization which helps in determining the cumulative effect of sequentially introduced positive or negative values. The waterfall chart is also known as a Flying Bricks Chart or Mario Chart due to the apparent suspension of columns in mid-air...

also known as a "Walk" chart, is a special type of floating-column chart.
• A Tree Map
Treemapping
In information visualization and computing, treemapping is a method for displaying hierarchical data by using nested rectangles.- Main idea :...

where the areas of the rectangles correspond to values. Other dimensions can be represented with colour or hue.

### Field-specific charts

Some types of charts have specific uses in a certain field
This gallery shows:
• Stock market prices are often depicted with a open-high-low-close chart
Open-high-low-close chart
An open-high-low-close chart is a type of chart typically used to illustrate movements in the price of a financial instrument over time. Each vertical line on the chart shows the price range over one unit of time, e.g. one day or one hour...

with a traditional bar chart of volume at the bottom.
• Candlestick chart
Candlestick chart
A candlestick chart is a style of bar-chart used primarily to describe price movements of a security, derivative, or currency over time.It is a combination of a line-chart and a bar-chart, in that each bar represents the range of price movement over a given time interval. It is most often used in...

s are another type of bar chart used to describe price movements of an equity over time.
• A Kagi chart
Kagi chart
The Kagi chart is a chart used for tracking price movements and to make decisions on purchasing stock. It differs from traditional stock charts, such as the Candlestick chart by being mostly independent of time...

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
Sparkline
A sparkline is a type of information graphic characterized by its small size and high data density. Sparklines present trends and variations associated with some measurement, such as average temperature or stock market activity, in a simple and condensed way...

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
Gantt chart
A Gantt chart is a type of bar chart that illustrates a project schedule. Gantt charts illustrate the start and finish dates of the terminal elements and summary elements of a project. Terminal elements and summary elements comprise the work breakdown structure of the project. Some Gantt charts...

to show the timing of tasks as they occur over time.

### Well-known named charts

Some of the better-known named charts are:
Some specific charts have become well known by effectively explaining a phenomenon or idea.
• An Allele chart
Allele chart
An Allele chart is a type of chart that shows the interaction of two data points at the grid intersection of their respective axes. The most common example of such a chart is from the multiplication table chart taught in many United States elementary schools, though the actual origins of this type...

is a chart originating from the study of genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

to show the interaction of two data points in a grid.
• A Gantt chart
Gantt chart
A Gantt chart is a type of bar chart that illustrates a project schedule. Gantt charts illustrate the start and finish dates of the terminal elements and summary elements of a project. Terminal elements and summary elements comprise the work breakdown structure of the project. Some Gantt charts...

helps in scheduling complex projects.
• The Nolan chart
Nolan Chart
The Nolan Chart is a political diagram popularized by the American libertarian David Nolan. He reasoned that virtually all human political action can be divided into two general categories: economic and personal...

is a libertarian political chart.
• A PERT chart
Program Evaluation and Review Technique
The Program ' Evaluation and Review Technique, commonly abbreviated PERT, is a statistical tool, used in project management, that is designed to analyze and represent the tasks involved in completing a given project...

is often used in project management
Project management
Project management is the discipline of planning, organizing, securing, and managing resources to achieve specific goals. A project is a temporary endeavor with a defined beginning and end , undertaken to meet unique goals and objectives, typically to bring about beneficial change or added value...

.
• The Pournelle chart
Pournelle chart
The Pournelle chart, developed by Jerry Pournelle , is a 2-dimensional coordinate system which can be used to distinguish political ideologies...

is a political chart to categorize state and rational ideologies.
• The Smith chart
Smith chart
The Smith chart, invented by Phillip H. Smith , is a graphical aid or nomogram designed for electrical and electronics engineers specializing in radio frequency engineering to assist in solving problems with transmission lines and matching circuits...

*For the magazine, see Radio-ElectronicsRadio electronics is the sub-field of electrical engineering concerning itself with the class of electronic circuits which receive or transmit radio signals....

.

• Diagram
Diagram
A diagram is a two-dimensional geometric symbolic representation of information according to some visualization technique. Sometimes, the technique uses a three-dimensional visualization which is then projected onto the two-dimensional surface...

• Edward Tufte
Edward Tufte
Edward Rolf Tufte is an American statistician and professor emeritus of political science, statistics, and computer science at Yale University. He is noted for his writings on information design and as a pioneer in the field of data visualization....

• Exploratory data analysis
Exploratory data analysis
In statistics, exploratory data analysis is an approach to analysing data sets to summarize their main characteristics in easy-to-understand form, often with visual graphs, without using a statistical model or having formulated a hypothesis...

• Information graphics
Information graphics
Information graphics or infographics are graphic visual representations of information, data or knowledge. These graphics present complex information quickly and clearly, such as in signs, maps, journalism, technical writing, and education...

• Graphic organizer
• Mathematical diagram
Mathematical diagram
Mathematical diagrams are diagrams in the field of mathematics, and diagrams using mathematics such as charts and graphs, that are mainly designed to convey mathematical relationships, for example, comparisons over time.- Argand diagram :...

• Official statistics
Official statistics
Official statistics are statistics published by government agencies or other public bodies such as international organizations. They provide quantitative or qualitative information on all major areas of citizens' lives, such as economic and social development, living conditions, health, education,...

• Plot (graphics)
Plot (graphics)
A plot is a graphical technique for representing a data set, usually as a graph showing the relationship between two or more variables. The plot can be drawn by hand or by a mechanical or electronic plotter. Graphs are a visual representation of the relationship between variables, very useful for...