Chart
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Chart".

A pie chart.

A chart or graph is a type of information graphic or graphic organizer that represents tabular numeric data and/or functions. Charts are often used to make it easier to understand large quantities of data and the relationship between different parts of the data. Charts can usually be read more quickly than the raw data that they come from. 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 are more easily understood when presented in a horizontal bar chart^{citation needed}. 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.

Usage note: many information graphics or diagrams include the word "chart" in their name but are covered in those other articles (e.g., flowchart, org chart, smith chart).

Types of charts

Common charts

Line chart of Speed Vs Time

• A scatterplot uses Cartesian coordinates to show the relation of two or more quantitative variables.
• A histogram typically shows the quantity of points that fall within various numeric ranges (or bins).
• A bar graph uses bars to show frequencies or values for different categories.
• A pie chart shows percentage values as a slice of a pie.
• A line chart is a two-dimensional scatterplot of ordered observations where the observations are connected following their order.

Less-common charts

• A box plot (or box-and-whiskers plot) shows information about the distribution (minimum, maximum, mean average, etc.) along a single axis.
• A bubble chart is a two-dimensional scatterplot where a third variable is represented by the size of the points.
• A doughnut chart
• A Polar area diagram (developed by Florence Nightingale) is an enhanced form of pie chart.
• A radar chart (or "spider chart") is a two-dimensional chart of three or more quantitative variables represented on axes starting from the same point.
• A ternary plot is a barycentric plot on three variables which sum to a constant..
• A waterfall chart also known as a "Walk" chart, is a special type of floating-column chart.

Field-specific charts

Some types of charts have specific uses in a certain field

• Stock market prices are often depicted with a 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.
• Interest rates, temperatures, etc., at the close of the period are plotted with a line chart.
• Scatter charts plot readings of two variables simultaneously as dots between the X-axis and the Y-axis, such as for price and earnings.
• Marketers use a lift chart to highlight performance.
• Project planners use a Gantt chart to show the timing of tasks as they occur over time.
• A phase diagram denotes the equilibrium conditions between thermodynamically-distinct phases.

Well-known (named) charts

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.
• Bode plots are used in Control Theory.
• The Dalitz plot is a scatterplot which represents the relative frequency of manners in which the products of certain three-body decays may move apart.
• A Gantt chart helps in scheduling complex projects.
• A Lineweaver-Burk plot is used to represent and determine enzyme kinetics.
• Nichols plots are used in Control Theory.
• The Nolan chart is a libertarian political chart.
• Nyquist plots are used in Control Theory.
• A PERT chart is often used in project management.
• The Pournelle chart is a political chart to categorize state and rational ideologies.
• The Smith chart serves in radio electronics.

See also

• Edward Tufte
• Exploratory data analysis
• Flowchart
• Information graphics

References

This article does not cite any references or sources. (May 2007) Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.