Creating a 2-D Column Chart

Column charts are mainly used to compare one item to another, or to compare different items over a period of time. Column charts are effective in showing dramatic changes from one category to another. Here’s the 2-D column chart that we’re going to produce in this section of the tutorial:-

Data for the Column Chart

The data for the column chart has already been prepared and stored by Deltagraph. It is held in the Samples folder within the main Deltagraph folder (called Dg4 on the system that this tutorial was produced on). To load the data, proceed as follows:-

1. Select Open from the File menu.
2. Locate and open the Samples folder.
3. Open the file Business.Dg4.

When loaded, the data is displayed as follows (after changing the page name by selecting Name Page from the View menu and setting the name of the data page to ‘2-D Column’):-

How Column Charts Work

If you are unfamiliar with column charts, they work as follows: the data in the first column (i.e. in this case the years 1987 to 1997) will be used to label the ‘X’ axis (i.e. the horizontal axis), with the data in subsequent columns being plotted against each year and represented as a rectangular column whose height is directly proportional to the particular value against (in this case) each country. For example, for the year 1987, the United States has the highest value (120) and France has the lowest value (20). For that year, the USA will be represented on the column chart by the highest column and France will be represented by the lowest column, with the other countries being represented by columns whose heights lie between those of the USA and France, with Canada being 2^nd highest, Mexico 3^rd highest, the UK 4^th highest, and Japan 5^th highest. In order to easily compare values across the years, each country’s column (in this example) is assigned a different colour; the USA is blue, Mexico is red, Canada is green, and so on. Using colour may not always be appropriate if the chart can only be displayed on a non-colour device. In that case, rather than colours, different patterns are used to represent the different countries. (Notice that we don’t, in this case, know what the values associated with each country actually represent. They could represent anything capable of numeric representation and comparable across the six countries).

Plotting the Column Chart

Firstly, select the Chart Gallery from the Data menu and, in the dialog box which is displayed, set Category to ‘Bars/Cols’, select ‘2-D’ for Kind, and select Column chart from the gallery, as follows:-

Now click on OK. The following Deltagraph window should be displayed:-

Now:-

1. Type ‘Timespan’ into cell A13, and ‘Product X Sales’ into cell B13.

2. Then click on ‘Titles’ in the floating window, select cell A13 and click on ‘X Title’.

3. Similarly, select cell B13 and click on ‘Y Title’.

4. Finally, select all the data for the chart by dragging from the top-left cell to the bottom cell (F11) in the France column.

The Deltagraph window should now look something like:-

Now click on ‘Plot’ in the floating window. Then, after selecting Hide Background from the Page menu, the column chart should be drawn as follows:-

... which is the same as the chart we set out to draw at the start of this section.

2-D Column Chart Options

If (making sure that the 2-D column chart is selected) you select Options... from the Chart menu, the following dialog box should appear:-

The various parameters that can be set operate as follows:-

• Percentage changes the value axis and shows each data graphic (i.e. column in this case) as a percentage of the whole; the top value changes to 1.
• Clip Data hides or "clips off" any data plotted outside the chart grids.
• Show Data Only displays only the data graphics (i.e. columns in this case) , hiding all other chart elements including the frame and labels.
• Show Frame provides a back plane to the chart, but does not affect the grid. This option must be selected if you want to fill the chart with a pattern or colour or use a shadow.
• Show Additional Category Axis displays an additional category axis opposite the original axis. You can format the additional axis independently from the original axis. You can also set different font styles, and so on, for each set of axis labels. The additional axis can also be dragged and offset. Turning on this option is the same as choosing Overlay... from the Chart menu and turning on an additional category axis.
• Show Additional Value Axis displays an additional value axis opposite the original value axis. You can format the additional axis independently from the original axis. You can also set different font styles, and so on, for each set of axis labels. The additional axis can also be dragged and offset. Turning on this option is the same as choosing Overlay... from the Chart menu and turning on an additional value axis.
• Show Legend is defaulted to on. If you do not need the legend, deselect it in the checkbox. (This is the same as selecting Legend from the Chart menu and turning off Show Legend.
• Connect Between Series draws connecting lines between all the data points of the same series, in the colour of those data series.
• Grids on Top of Data draws the chart grid on top of the data markers so that the grid is not obscured. This can help to maintain a perspective on your data values when you have data markers that cover large areas of the plot frame.
• Bar Placement shows the following dialog so you can control the width and position of the data graphics. The dialog graphic reflects the number of data series in your chart.

• The Category Gap controls the space between data graphics and grid lines on the category axis based on a percentage of the bar width. To change the category gap, drag the lower bar-sizing handles (squares), enter any value between 1 and 1000, or click the direction arrows to scroll through the percentage options.
• The Series Gap controls the space between each data graphic based on a percentage of the bar width. To change the series gap, drag the upper bar-sizing handles (squares), enter any number between -100 and 1000, or click the direction arrows to scroll through the percentage options.

Click on the Show button to preview your changes without exiting the dialog. This allows you to experiment with different options and assess their effects without committing to a redrawing of the chart. If selected, the dialog box will shrink to its title bar. You can restore it by clicking on the zoom box (second from the right). You can drag the dialog box out of the way by dragging on its title bar.

When you have achieved the required effect, click on OK. If you want to exit from the dialog box without making any changes, click on Cancel.

Example

As an example of the effects of varying the options, try setting the Connect Between Series option as follows:-

And then set the Bar Placement options as follows:-

Now redraw the graph. It should look like:-

Try experimenting with the various options to see the sorts of effects produced.

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