# Creating XY (Scatter) and Line charts

Applies to |
---|

Microsoft Office Excel 2003 Microsoft Excel 2000 and 2002 |

XY (Scatter) charts and Line charts look very similar, especially when a Scatter chart is displayed with connecting lines. However, there's a big difference in the way each of them displays data. The main difference is the way each of these chart types plots data on the x-axis.

- A Line chart distributes category data evenly along the horizontal category axis (category axis: A chart axis that represents the category for each data point. It displays arbitrary text values like Qtr1, Qtr2, and Qtr3; it cannot display scaled numerical values.) (x-axis), and distributes all value data evenly along the vertical value axis (value axis: A chart axis that displays scaled numerical values.) (y-axis).
- A Scatter chart has two value axes, showing one set of numerical data along the x-axis and another along the y-axis. It combines these values into single data points and displays them in uneven intervals, or clusters.

For example, let's examine how the same daily rainfall and particulate data of the following worksheet is displayed in a Scatter chart and a Line chart.

When you use this worksheet data to create a Scatter chart, the daily rainfall values from column A of the worksheet will be displayed as x-values on the horizontal axis, and the particulate values from column B will be displayed as y-values on the vertical axis, as shown in the following picture.

The first data point to appear in the Scatter chart represents both a y-value of 137 (particulate) and an x-value of 1.9 (daily rainfall). These numbers come from both columns of row 9 on the worksheet.

In the following Line chart, however, the same daily rainfall and particulate data is displayed as two separate data points, which are evenly distributed along the horizontal axis.

Notice how the particulate y-value of 137 and the daily rainfall x-value of 1.9 are displayed as separate data points in this Line chart. Neither of these data points are the first data point displayed in the chart — instead, the first data point for each of the data series (data series: Related data points that are plotted in a chart. Each data series in a chart has a unique color or pattern and is represented in the chart legend. You can plot one or more data series in a chart. Pie charts have only one data series.) comes from the first data row (row 2) of the worksheet.

## Axis type and scaling differences

Scatter charts and Line charts also differ in the way they use axis types and scaling:

- The x-axis of a Scatter chart can only be a value axis. This means that only numeric data is displayed on this axis. To display this numeric data with greater flexibility, you can change the scaling options on this axis.
- The x-axis of a Line chart can be either a category or a time axis, both of which can display non-numeric data. Depending on which data is used, the scaling options are limited compared to the scaling options of the Scatter chart's x (value) axis.

You can see what axis type is used in your chart on the **Scale** tab of the **Format Axis** dialog box. Select the axis, and then click **Selected Axis** on the **Format** menu.

## When to use a Scatter chart

Scatter charts are commonly used for displaying and comparing numeric values, such as scientific, statistical, and engineering data. You should use a Scatter chart if you want to change the scale of the x-axis, or make it a logarithmic scale. You can use this chart type to effectively:

- Display worksheet data that includes pairs or grouped sets of values. You can adjust the independent scales of a Scatter chart to reveal more information about the grouped values.
- Show similarities between large sets of data. Rather than showing the differences between data points (data points: Individual values plotted in a chart and represented by bars, columns, lines, pie or doughnut slices, dots, and various other shapes called data markers. Data markers of the same color constitute a data series.), a Scatter chart can point out interesting similarities.
- Compare large numbers of data points without regard to time. The more data that you include in a Scatter chart, the better the comparisons that you can make.

Scatter charts can be displayed with or without lines to connect the data points, and connecting lines can be displayed with or without data markers (data marker: A bar, area, dot, slice, or other symbol in a chart that represents a single data point or value that originates from a worksheet cell. Related data markers in a chart constitute a data series.).

## When to use a Line chart

Line charts can display continuous data over time, set against a common scale, and are therefore ideal for showing trends over time. As a general rule, you may want to use a Line chart if your data has non-numeric x-values. (For numeric x-values, it's usually better to use a Scatter chart.)

For example, if dates were added to the daily rainfall and particulate worksheet data, a Line chart including those dates on the time (x) axis would be much easier to read (as shown in the following picture).

To show the values for both data series, a second value (y) axis was added. Second axes are very useful in both Scatter and Line charts.

Line charts display lines through a set of data points, with or without data markers. The data series in Line charts can be stacked. And, unlike Scatter charts, Line charts can even be displayed with a 3-D visual effect.

## Create a Scatter or Line chart

- Arrange your data so that the x-values are in the first row or column of your worksheet, and the y-values are located in adjacent rows or columns.
- Select the range of x- and y-values that you want to plot in the chart.
- Click
**Chart**on the**Insert**menu to start the Chart Wizard. - In the
**Chart type**box, select**XY (Scatter)**or**Line**. - Under
**Chart sub-type**, click the chart sub-type you want to use.

For a quick preview of the chart you are creating, click **Press and Hold to View Sample**.

- Click
**Next**, and continue with steps 2 through 4 of the Chart Wizard.

For help on any of the steps, click the question mark (**?**) on the Chart Wizard title bar.