# A Primer on Charts

People often use “charts” and “graphs” to describe the largest family of visualizations. They may choose the term based on an academic convention. Or because they believe the distinction between them is important. Sometimes the terms complement one another. Sometimes they are synonymous. And sometimes people use them to make minor distinctions between types of visualizations. This glossary uses Charts to make it easier for you to navigate a variety of subcategories of data visualizations best grouped by Mark Type and Analytical Function.

## Inspirational examples of charts from the community

We’ve selected a few visualizations from the Tableau community to highlight how beautifully data can be portrayed. For more practical examples check out the different Analytical Functions or individual visualization types.

## So, what is a chart?

A chart is a representation of data in the form of a graph, diagram, map, or tabular format. This could make the other two families, Geospatial and Tables, subfamilies of it. We distinguish between them to help you identify when one works better for your data. Consider the most common Charts: Scatterplots, Bar Charts, Line Graphs, and Pie Charts. These Chart types, or a combination of them, provide answers to most questions with relational data. They are the backbone of performing visual analysis on non-geospatial data.

Visualizing data with Charts relies on drawing points using cartesian coordinates (Ex. X, Y, Z) based on a set of dimensions and measures. Dimensions (Ex. categories, dates, etc.) group the measures for analysis. The measures are then rendered on the corresponding coordinates to create a visualization. Some types of visualizations excel at displaying many dimensions (Ex. Ordered Bar Charts), while others can only support a few with clarity (Ex. Pie Charts).

Each Chart type has its own strengths and weaknesses. But if used well people will understand the data better. When you pay attention to aesthetic conventions you can also make your visualization beautiful. You will combine both form and function to affect the viewer’s perception of the data.

## Key types of charts

The table below contains a tagline for the most common types of Charts. As the glossary expands in depth and breadth more types will be added and each will have a page dedicated to showing practical examples and explaining when to use them.

##### Bar Chart

Used to categorize elements based on size. Can be ordered or unordered based on the nature of the dimensions.

##### Line Graph

Best used to show change-over-time. Multiple lines can be used to compare data sets.

##### Dual Axis Chart

Charts combining symbols, bars, or lines to explore relationships in the data between axes or dimensions.

##### Scatterplot

Used to explore the correlation between two measures with independent axes. Often combined with trendlines.

##### Gantt Chart

A niche bar chart used to display segments of time. Useful for exposing time usage or visualizing intervals.

##### Pie Chart

A common, but limited, visualization used to show how a few dimensions compare to one another and the whole.