6
Creating graphs in Discoverer

This chapter explains how to create graphs in Discoverer to answer typical business questions, and contains the following topics:

• "What is a Discoverer graph?"

• "About using graphs in Discoverer"

• "More about worksheets and graphs"

• "About saving Discoverer graphs"

• "About components of a Discoverer graph"

• "About graph types and sub-types"

• "About graph types available in Discoverer"

• "Notes about creating bubble graphs"

• "Notes about creating high-low-close stock charts"

• "Notes about creating dual-Y charts"

• "Notes about creating pie charts"

• "How to create a graph"

• "How to edit a graph"

• "How to change the position of a graph on screen"

• "How to delete a graph"

What is a Discoverer graph?

A Discoverer graph is a pictorial representation of worksheet data. For example, you might create a graph to enable you to easily analyze trends in your data.

About using graphs in Discoverer

Discoverer provides a wide range of graphs to help you analyze data visually (e.g. area, bar, line, and scatter graph). For a complete list of graph types available in Discoverer, see "About graph types available in Discoverer".

Discoverer provides the Graph Wizard to help you create and edit graphs. The Graph Wizard helps you:

• choose a graph type

• choose the data that you want to represent in a graph

• specify how the graph will look

More about worksheets and graphs

In Discoverer, you create a graph for the items currently displayed on the worksheet. If you want to plot items on a graph that are not currently displayed, make sure that you display the items on the worksheet before you start. If you do not want to plot items displayed on the worksheet, make sure that you remove the items from the worksheet before you start.

When you create graphs in Discoverer, each Discoverer worksheet can have one graph. If you already have a graph in a worksheet and want to create a completely new graph, you do the following:

• delete the existing graph (see "How to delete a graph"), then create a new graph (see "How to create a graph")

Alternatively, you can also existing edit graphs (see "How to edit a graph"). If you change the data displayed in a worksheet, the graph automatically updates to show the new data.

Note:

• To edit a Discoverer graph, you must use the same Discoverer tool that you used to create the graph. In other words:
  • if you created a graph using Discoverer Plus, you must use Discoverer Plus to edit the graph

  • if you created a graph using Discoverer Desktop, you must use Discoverer Desktop to edit the graph

About saving Discoverer graphs

When you save a workbook, Discoverer saves graphs automatically for you as part of the worksheets in the workbook. In other words, you do not have to explicitly save graphs. Any changes you make to the graph are also saved automatically when you save the workbook.

About setting font options

Each page of the Graph Wizard enables you to change the default font options for various graph components. For example, the X-axis title, the X-axis label, and the legend font. You use the "Graph Wizard: Font dialog" to set the font style.

The figure below shows how the Title Font button on the "Graph Wizard: Titles, Totals, and Series dialog" is used to display the "Graph Wizard: Font dialog".

Figure 6-1 The Graph Wizard font dialog

Text description of the illustration gfont.gif

The "Graph Wizard: Font dialog" enables you to change the default font styles (e.g. font, font size, font color).

About components of a Discoverer graph

Discoverer gives you great flexibility when producing graphs, which enables you to configure every component of a graph. The figure below shows typical components of a Discoverer graph.

Figure 6-2 Components of a Discoverer graph

Text description of the illustration gw-graph.gif

Key to figure:

1. The graph title.

2. The y-axis label.

3. The plot area, showing worksheet data represented on the graph.

4. The x-axis label.

5. Tick label.

6. The graph legend.

About graph types and sub-types

To present your worksheet data visually in Discoverer, you can choose from a wide range of graph types. For example:

• bar graph

• line graph

• pie chart

Each graph type has one or more variations, or sub-types. For example, the Bar graph type has three sub-types:

• area

• percent area

• stacked area

Most graph sub-types have a three-dimensional effect that you can switch on and off as required (using the 3D-Effect check box).

Note: 3D-Effect should not be confused with three-dimensional graphs, such as 3D-Cube and Surface, which are used to represent multi-dimensional data.

Some graphs also have a dual-Y sub-types, which have two Y-axes. Dual-Y graphs are useful for showing the following types of data:

• data of different measures (such as sales on the Y1-axis and profit on the Y2-axis)

• data of different scales (such as region sales on the Y1-axis and percent of total sales on the Y2-axis)

About graph types available in Discoverer

The table below shows the graph types that are available in Discoverer.

Table 6-1 Discoverer graph types

Graph icon	Graph name and description
Text description of the illustration s_bar_ve.gif	Bar graph - compares values using vertical bars. Each value is represented by a single bar. Bar graphs shows variation over a period of time or illustrates comparisons between values. The stacked sub-type shows each value's relationship to a whole. Bar graphs can have two Y axes (for more information, see "Notes about creating dual-Y charts").
Text description of the illustration s_bar_ho.gif	Horizontal bar graph - compares values using horizontal bars. This graph type is identical to a bar graph except that the bars lie horizontally, rather than standing vertically. The stacked sub-type shows each value's relationship to a whole. Bar graphs can have two Y axes (for more information, see "Notes about creating dual-Y charts").
Text description of the illustration s_line_v.gif	Line graph - shows trends or changes in data at even intervals. Data is represented as a line that connects a series of data points.
Text description of the illustration s_point_.gif	Point graph - shows trends or changes in data at even intervals. Point graphs are similar to a line graph in that data is represented by points, however the data points are not connected by a line.
Text description of the illustration s_area_v.gif	Area graph - shows trends or changes in data using filled-in areas.
Text description of the illustration s_pie.gif	Pie chart - shows data as sections of a circle, similar to slices of a pie. A pie chart shows the proportion of parts to the whole. It is useful for emphasizing a significant element, such as the highest value. Note that a pie chart displays only one row or one column of data at a time (for more information, see "Notes about creating pie charts").
Text description of the illustration s_polar.gif	Polar graph - shows data in a circular scatter graph. The circular shape enables you to present cyclical data and is especially useful for showing directional data.
Text description of the illustration s_scatte.gif	Scatter graph - displays data as points scattered over the plot area. Each point is a value whose coordinates are specified by two numeric measures. A scatter graph is useful for showing relationships between two measures, for example Sales and Cost. All points are the same size, regardless of their value.
Text description of the illustration s_bubble.gif	Bubble graph - shows data in a similar way to a scatter graph, but with an extra dimension that uses the size of the bubbles. Each bubble is a value whose coordinates are specified by three numeric measures. A bubble graph is useful for comparing data that has three measures (for more information, see "Notes about creating bubble graphs").
Text description of the illustration s_stock_.gif	High-low-close stock chart - shows highest stock price, lowest stock price, and closing stock price as bands on a time axis. Stock charts are useful for comparing the prices of different stocks or the stock price of an individual stock over time (for more information, see "Notes about creating high-low-close stock charts").
Text description of the illustration s_threed.gif	3D graph - shows three-dimensional data in a true three-dimensional graph, where you can see an X axis, a Y axis, and a Z axis. 3D graphs have a floor, a wall, and a background. There are four 3D graph sub-types: 3D Bar, 3D Cube, 3D Area, and 3D Surface. 3D graphs are useful for showing trends or to compare values. Note: This graph type is not the same as a two dimensional graph with the 3D Effect turned on. The 3D Effect simply adds depth to any graph type.
Text description of the illustration s_pareto.gif	Pareto graph - shows trends across groups periodically and cumulatively. Each group is displayed as a bar chart column. A plotted line also shows the cumulative value across groups.

Notes about creating bubble graphs

To create meaningful graphs in Discoverer, you need to have the correct worksheet configuration for the style of graph that you want to use.

When you create bubble graphs, follow these guidelines:

• You need at least three items per bubble:
  • the X item - the bubble's location on the X-axis

  • the Y item - the bubble's location on the Y-axis

  • the Z item - the size of the bubble (which should be positive numbers)

The figure below shows an example Discoverer worksheet and the worksheet data plotted on a bubble graph.

Figure 6-3 Example Discoverer worksheet and bubble graph

Text description of the illustration gr_bub.gif

For example, you might have the following items on a bubble graph (see figure above):

• store size as the X item (the 'Store size m2' item on the worksheet)

• advertising costs as the Y item (the 'Advertising $' item on the worksheet)

• sales as the Z item (the 'Sales $' item on the worksheet)

You could then see whether the largest stores with the most advertising generated the highest sales revenue.

The figure above shows how worksheet data is represented on a bubble graph. The bubbles represent Sales. A large bubble represents a large sales revenue. A small bubble represents a small sales revenue.

Notes about creating high-low-close stock charts

When you create high-low-close stock charts, follow these guidelines:

• You need at least three items in the following order:
  • high price

  • low price

  • closing price

    Figure 6-4 Example worksheet and high-low-close stock chart

    
    
    Text description of the illustration gr_stock.gif

  For example, the figure above shows a worksheet configuration for charting a stock price over time (January, February and March). The worksheet data is arranged 'Series by row'.

• Stock values for high, low, and closing prices must appear on the same row or column series as groups of three.

• To display high, low, and closing prices for more than one period, the data must be in multiples of three. For example, three columns for period one, three columns for period two, and so on.

• If a high-low-close stock chart contains more than stock, and prices overlap, some stock values will obscure other stock values.

Notes about creating dual-Y charts

When you create dual-Y graphs, follow these guidelines:

• You can use the dual-Y facility with the following types of graph:
  • bar

  • line

  • area

The figure below shows an example dual-Y bar graph with a Y axis for sales and a second Y axis for costs.

Figure 6-5 Example worksheet and dual Y graph

Text description of the illustration gr_dualy.gif

• Dual-Y graphs require at least two items.

• By default, the series are displayed in the following way:
  • series one is displayed on the Y1 axis

  • series two is displayed on the Y2 axis

  • all subsequent series are displayed on the Y1 axis

In the figure above, the Y1 axis represents sales on the scale 0 to 1 million. The Y2 axis represents costs on the scale 0 to 50,000. You can therefore analyze sales and costs side by side even though they use different scales.

Notes about creating pie charts

When you create a pie chart, you choose which row or column you want to represent. The figure below shows how a row of data is represented on a pie chart.

Figure 6-6 Using a worksheet row to create a pie chart

Text description of the illustration pie3.gif

The figure below shows how a column of data is represented on a pie chart.

Figure 6-7 Using a worksheet column to create a pie chart

Text description of the illustration pie2.gif

How to create a graph

Discoverer provides the Graph Wizard to help you create a graph of your worksheet data.

Each time you use the Graph Wizard, Discoverer saves the settings as defaults for the next graph that you create. If at any time you want to use default settings for the remaining steps in the Graph Wizard, simply click the Finish button.

To create a graph:

1. Choose Graph | New Graph to display the "Graph Wizard: Graph Type dialog", and choose a graph style from the list of graph types and graph sub-types.

   
   
   Text description of the illustration graph_1.gif

   For more information about choosing a graph type, see "About graph types available in Discoverer".

2. Click Next to display the "Graph Wizard: Titles, Totals, and Series dialog", where you:
   • (optional) define a graph title

   • use the What would you like to display? options to select what data you want to display (i.e. data only, totals only, or both data and totals)

   • use the Graph series by options to select whether to plot data by row or column

   • (optional) when creating a pie chart, you select which row or column you want to plot on the graph

     
     
     Text description of the illustration graph_2.gif

If you are creating a pie chart, the Pie Chart Options button is active.

3. (optional) To select which column or row to plot on the graph:
   1. Click Pie Chart Options to display the "Graph Wizard: Pie Chart Options (column) dialog" or "Graph Wizard - Pie Chart Options (row) dialog".

   2. Select the row or column that you want to graph from the list of items.

   3. Click OK.

   Note: When you click Next, you go straight to the "Graph Wizard: Plot Area dialog". This is because you do not define X or Y axes for pie charts.

4. Click Next to display the "Graph Wizard: X Axis dialog", where you specify how the X axis is displayed.

   
   
   Text description of the illustration grphxaxs.gif

5. Click Next to display the "Graph Wizard: Y1 Axis dialog", where you specify how the Y axis is displayed.

   
   
   Text description of the illustration grphyaxs.gif

6. (optional) If you are creating a dual-Y graph, click next to display the "Graph Wizard: Y2 Axis dialog", where you specify how the Y axis is displayed.

   For more information about creating dual-Y graphs, see "Notes about creating dual-Y charts".

7. Click next to display the "Graph Wizard: Plot Area dialog", where you specify the color and style of plotted data.

   
   
   Text description of the illustration grphplot.gif

8. Click Next to display the "Graph Wizard: Legend dialog", where you specify the graph legend that provides information about how items are represented on the graph.

   
   
   Text description of the illustration grphlgnd.gif

9. Click the Finish button to save the details and display the graph.

Discoverer displays the graph on the worksheet.

By default, graphs are displayed at the right-hand side of worksheet data. To change where a graph is displayed, choose Graph | Display Graph and choose a position from the list of options.

For information about positioning graphs, see "How to change the position of a graph on screen".

How to edit a graph

You edit a graph to change how it is displayed on a worksheet. For example, you might want to change the graph type, change the axis labels, or change the color of plotted items.

To edit a graph:

1. Choose Graph | Edit Graph to display the "Graph Wizard: Graph Type dialog".

   You can click the tabs along the top of the dialog to do directly to tabs that you want to edit.

2. Display the tab for the graph area that you want to change, and make changes as required.

3. Click OK to save changes and close the Graph Wizard dialog.

Discoverer updates the graph as specified.

Notes:

• To see changes take effect immediately, click Apply at any time. The graph is updated within the Discoverer worksheet area.

How to change the position of a graph on screen

You change a graph's position on screen when you want to change where it is displayed in relation to the worksheet data. For example, you might want to display a graph below worksheet data, or display a graph in a separate window.

To position a graph:

1. Choose Graph | Display Graph and choose one of the following menu options:
   • Separate Window - display the graph in a window that floats above the worksheet window. You can move the graph window to any location on your screen by dragging it with the mouse.

     Note: If you close the separate window, choose Graph | Display Graph and choose a display option to re-display the graph.

   • Right of Data - display the graph to the right of the worksheet.

   • Left of Data - display the graph to the left of the worksheet.

   • Above Data - display the graph above the worksheet.

   • Below Data - display the graph below the worksheet.

   • Hide/Unhide Graph - display the graph or hide the graph. The Hide option does not delete the graph.

   Discoverer displays the graph in the position that you specified.

Notes:

• When you choose Graph | Display Graph and choose a position from the list of options, you change how the graph is positioned on screen. This does not affect how a worksheet and graph print out. For example, Discoverer always prints graphs on a separate page, after the worksheet data.

• For information about how to delete a graph permanently from a worksheet, see "How to delete a graph".

• If a graph is too large to fit completely inside its window panes without scroll bars, choose Graph | Fit to window. The graph resizes so that it is completely visible inside its window.

How to delete a graph

You delete a graph when you no longer want to use it, and will not require the graph later. For example, you might want to delete a temporary graph that you created to produce a printed report.

To delete a graph:

1. Choose Graph | Delete Graph.

   A warning message appears.

2. Click Yes to delete the graph.

   The graph is removed from the worksheet.

Notes:

• If you want to remove a graph without deleting it, choose the Graph | Display Graph | Hide Graph option. You can then display the graph later if required without having to recreate the graph.