Noting the Historical Events

Now for the finishing touches – adding some emphasis to the body of the chart and noting the historical events that triggered the changes in value. First the easy one – we should add the note element:

INTEREST OF NATIONAL DEBT,1720,0.6

(you can drag a chart note from the Chart Elements tab and just paste this if you like) and press Enter to see the effect.

Here you can see that I have also changed the note font from its default setting to 10pt Times Italic, Black. Notes are written (baselined, left-aligned by default) at the x-y co-ordinates you specify – they can be used for pretty well any arbitrary text, and you can even write them in the margins by using numbers just outside the range of your axes.

To get the events labelled, we could start by trying the obvious GraPL property of ‘Value Labels’. This is not included in the standard set of linechart properties, as it is fairly uncommon and would clutter the property-sheet unnecessarily. We must go and fetch it from the ‘Properties’ tab which has a comprehensive set of all the properties GraPL knows about:

Here I have selected 3 handy-looking extra properties, and I am just about to drop them on the chart definition for the linechart. You can see the heavy line in the grid which indicates where the new items will be inserted. Again we must change the font – the notes should be 6pt dark-red Times-Italic (Maroon is the official internet colour name for dark red!) – and check the ‘Values’ option in the line-graph style to have our labels drawn. The default for value labels is simply to write the data-value above the data-point, with a choice of left, right or centred alignment.

This is quite useful, but not what we want in this case. Fortunately, the same rules as we used for the X-ticks apply here – wherever GraPL expects a value which might be an array of data, you can put a column name, so we simply switch the Value Labels from ‘(auto)’ to ‘Event’ and set the style to ‘vertical’ and the job is virtually done! One final touch is to add a horizontal datum line at the £10M line – presumably this was a politically important number at the time – which you can do by pulling across a ‘Y-datum’ property and setting its value to 10. You might notice that I have changed the overall shape of the page from its default of 432pts wide by 324pts high to just 300pts high which exactly preserves the shape of the original.

Finally, we can explore some alternative ways of publishing the completed chart. Save your work, start a copy of your favourite word-processor and proceed to the final topic in this tutorial.

Continue to: Exporting and Printing