# Which chart represents a single data series?

There are many types of charts in IBM® Cognos® Insight for presenting your data in a way that is meaningful to you and your users. To choose the appropriate type of chart, first d

There are many types of charts in IBM® Cognos® Insight for presenting your data in a way that is meaningful to you and your users.

To choose the appropriate type of chart, first define what you want the chart to communicate, and then identify the most effective chart to suit that purpose. Table 1. Types of charts Purpose of the chart Type of chart to use Show trends over time. Column chart, line chart, point chart Compare data. Bar chart, column chart Show the relationship of parts to the whole or highlight proportions. Pie chart Show the parts that contribute to the total and compare change over time. Stacked column chart Show groups of related data. Bar chart, column chart Emphasize the magnitude of change over time. Area chart Show the relationship between two measures. Scatter chart Show the relationships between three measures. Bubble chart Show trends over time or compare data with two measures. Combination chart Identify patterns of high and low values. Tree map

You can select the following formats for the chart types:

- standard

Standard charts compare specific values and represent discrete data, such as data for different regions or individual employees.

- stacked

Stacked charts compare the proportional contributions within a category, showing the relative value that each data series contributes to the total. The top of each stack represents the accumulated totals for each category.

- 100 percent stacked

100 percent stacked charts compare the proportional contributions across all categories, showing the relative contribution of each data series to the total. This format highlights proportions. When actual values are important, use another format.

- three-dimensional

Three-dimensional charts are a visually effective display for presentations. When exact values are important, such as for control or monitoring purposes, use another format. The distortion in three-dimensional charts can make them difficult to read accurately.

## Column charts

Column charts are useful for comparing discrete data or showing trends over time.

Column charts use vertical data markers to compare individual values.

## Line charts

Line charts are useful for showing trends over time and comparing many data series.

Line charts plot data at regular points connected by lines.

## Pie charts

Pie charts are useful for highlighting proportions.

They use segments of a circle to show the relationship of parts to the whole. To highlight actual values, use another chart type, such as a stacked chart.

Pie charts plot a single data series. If you need to plot multiple data series, use a 100 percent stacked chart.

## Bar charts

Bar charts are useful for plotting many data series.

Bar charts use horizontal data markers to compare individual values.

## Area charts

Area charts are useful for emphasizing the magnitude of change over time. Stacked area charts are also used to show the relationship of parts to the whole.

Area charts are like line charts, but the areas below the lines are filled with colors or patterns.

## Point charts

Point charts are useful for showing quantitative data in an uncluttered fashion.

Point charts use multiple points to plot data along an ordinal, or non-numeric, axis. A point chart is the same as a line chart without the lines. Only the data points are shown.

## Scatter charts

Scatter charts are useful for showing relationships between two measures.

Scatter charts use colored circles to represent two measures for each dimension. The x-axis represents one measure, and the y-axis represents a second measure.

For example, you create a scatter chart that shows Cost and Revenue by Product. Your scatter chart consists of one circle for each Product. Each Product circle is plotted on the chart based on Cost, on the x-axis, and Revenue, on the y-axis.

## Bubble charts

Bubble charts are useful for showing relationships between three measures.

Bubble charts use colored circles of different sizes to show three measures for each dimension. The x-axis represents one measure, the y-axis represents a second measure, and the size of the bubbles represent a third measure.

For example, you create a bubble chart that shows Cost, Revenue, and Quantity Sold by Product. Your bubble chart consists of one circle for each Product. Each Product circle is plotted on the chart based on Cost, on the x-axis, and Revenue, on the y-axis. The size of the circle represents the Quantity Sold for that Product.

## Combination charts

Combination charts are useful for showing a comparison of two measures over time.

Combination charts include a column chart and a line chart, both on the same x-axis. The column chart represents one measure, and the line chart represents a second measure. By default, the first measure in the content pane is represented by the columns and the second measure is represented by the line. If the y-axes do not have the same range of values, the y-axis on the left of the chart displays values for the columns, and the y-axis on the right of the chart displays values for the line. For example, you create a combination chart that shows Cost, Revenue, and Quantity Sold by Product. Your combination chart consists of columns that represent Revenue, and a line that represents Quantity Sold. Each product is represented by a column and a point on the line.Restriction: You cannot drag columns up or down to change their values in a combination chart. Because dragging is not supported for line charts, dragging is also not supported in combination charts.

## Tree maps

Tree maps are useful for showing patterns of high and low values.

Tree maps use colored rectangles of different sizes to show two measures for each dimension. A tree map is similar to a pie chart, in that the size of the rectangles identifies the proportion of the whole that is represented by each element.

For example, you create a tree map showing Revenue and Quantity Sold by Product Line and Product. Your tree map consists of several rectangles, one for each Product Line. Each Product Line rectangle contains several Product rectangles, and the size of the rectangle in proportion to the whole represents the product's Revenue, and the color of the rectangle represents the product's Quantity Sold.