Charts and PivotChart reports are a vital part of Microsoft Office Excel data analysis reporting because they are visually appealing and they make it easy for you to see comparisons, patterns, and trends in data. You can view charts, chart ranges, and PivotCharts in Excel Services. However, there are similarities and differences between Excel and Excel Services that you need to know to help you author and view charts and PivotCharts more effectively.

Chart and PivotChart display and size

A chart and PivotChart is a static image that redisplays upon data interaction

Using 3-D charts and 2007 Microsoft Office system 3-D graphic effects

Color quality can vary between computers

Authoring a chart and PivotChart: Best practice

Issue: A Logarithmic chart displays a null value on the horizontal (category) axis

Chart and PivotChart display and size

There are two ways that a chart or PivotChart is displayed in Microsoft Office Excel Web Access.

• Worksheet view   In Worksheet view (no named item is selected from the View drop-down list, or the Office Excel Web Access Named Item property is clear), the entire chart or PivotChart is displayed in its location in the worksheet. However, if the chart or PivotChart cannot fit in a scrolling region, it may be cropped. In this case, you can click the chart image to open the chart in a new window. For more information, see Navigate a workbook in Excel Services.
• Named Item view  In Named Item view, (a chart is selected from the View menu, or the workbook was saved so that only a chart is visible), the entire chart or PivotChart is displayed by itself.

In either case, the maximum size of a chart or PivotChart that you can display in Excel Services is one megabyte.

 Note    Although embedded charts on worksheets and original charts on chart sheets are supported for display in Excel Services, an embedded chart that a workbook author has copied or moved from a worksheet to a chart sheet is not supported for display.

A chart and PivotChart is a static image that redisplays upon data interaction

In Excel Services, a chart or PivotChart displays with current data. If you interact (filtering, sorting, and so on) with the data that a chart is based on, or interact (expanding or collapsing levels of data, showing and hiding subtotals, and so on) with the data in the associated PivotTable report of a PivotChart, a chart or PivotChart redisplays with the new data.

However, a chart or PivotChart is always displayed as a static image. So, you cannot click and follow a hyperlink on a chart or PivotChart, or interact with, change, or delete a chart or PivotChart.

Using 3-D charts and 2007 Microsoft Office system 3-D graphic effects

Most 3-D charts are supported for display in Excel Services, but they are converted to a 2-D equivalent. The following 3-D charts are not supported in Excel Services:

• 3D surface
• Wireframe 3D surface
• Contour surface
• Wireframe contour surface

If any chart contains 2007 Office release 3-D graphic effects, such as shadow, glow, warp, bevel, soft edges, recolor, and reflection, these effects are either removed or converted to an alternative effect.

Note that the 3-D chart and and 3-D graphic effects are preserved in the workbook, so you can still see them when you open the workbook on your client computer.

Color quality can vary between computers

You should be aware that color quality settings vary on a client and server computer. (From the Control Panel, click Display to open the Display Properties dialog box, and then click the Settings tab.) There are three settings:

• Highest (32 bit, 4 million colors).
• Medium (16 bit, 32,000 colors).
• Lowest (8 bit, 256 colors).

The color quality can make a difference in the clarity of the chart, especially if the colors that are used are not distinct enough for the user's current display setting. Because the chart image is created on the server computer, the setting on the server computer can limit the colors displayed in the chart, regardless of the color setting on the client computer.

Authoring a chart and PivotChart: Best practice

When authoring a workbook in Microsoft Office Excel 2007 for display in Excel Services, it's a good idea to preview the chart or PivotChart in the browser by using the Excel Services command under the Publish submenu on the Microsoft Office Button , and then by selecting the Open in Excel Services check box in the Save As dialog box. You may want to adjust the chart size or redesign the chart depending on what you see. Consider the following:

• Who are your users and what is the most common color quality setting for their computers? Do you need to change the colors in the charts to make them more clear?
• If the chart is cropped, can you move the chart in the worksheet, or move it to another worksheet so that the full chart is displayed?
• Does the chart display as intended? Do you need to adjust the size of the chart, or perhaps create several different charts to reduce it's size and complexity?
• If the chart uses 3-D graphic effects, does it display according to your needs in Excel Services, or do you need remove or minimize the use of these effects in Excel?

Issue: A Logarithmic chart displays a null value on the horizontal (category) axis

In Excel, you can create a custom line chart that uses a logarithmic scale on its value axis. If you inadvertently enter a negative or zero number, you get an alert and you are prevented from entering these incorrect values. However, in Excel Services, a user could enter negative or zero values if the cells that are used to plot these values are defined as workbook parameters, which do not have any way to prevent invalid data entry. In Excel Services, a negative or zero number displays as a null value on the category axis. To avoid this situation, make sure that a user enters a positive number. For more information, see Change workbook parameters in Excel Services.