Show Sys/Dys blood pressure values on one "floating verticle bar" per measurment.

Actually, this turned out to be a little more complex than I first imagined.

I think @Yellowbox was right on thinking a Stacked Column chart is the way to go, however, there is a problem with the numbers.

In using a Stacked Column, each data series is plotted above its partner - another words, given a systolic/diastolic of 120/80, the diastolic would be plotted from 0-80, then the 120 mm Hg Systolic value would be plotted above that, for a sum of 200 which should set all kinds of alarm bells ringing :)

To counter this, you could plot the difference between the systolic and diastolic values - Numbers actually makes this easy, but there are a few things to check:

There are a couple of noticeable tricks here.

First, there are two series plotted. Series 1 is the diastolic values:

and its style has been set to 'No Fill' and No Stroke so that it isn't visible:

The second series is actually the difference between the two values. This is achieved by entering a formula in the Series, rather than a reference:

Note that this series calculates Systolic - Diastolic values and that's what it plots (and stacks on top of the diastolic values).

Important thing here is to set the Value Labels to 'None', otherwise it would plot the difference values, which don't make sense on this chart. Instead, click the chart itself (no specific series) and check Inspector -> Series and turn on Summary Labels. This will add a label for the sum of the series, rather than the individual series:

The last thing I did was to check Inspector -> Chart and increase the 'Gaps Between columns' to 420%

This has the effect of narrowing the bars by putting more space between them.

Hope that helps.

If you are meticulous about your logging and always measure at regular intervals then a Stacked Column chart will do. But if your measurement intervals may vary from time to time then a Scatter Chart may be a better fit.

A Scatter Chart can be made to look almost exactly like a Stacked Column. The simple trick is to use Error Bars.

You can easily achieve different looks, including these:

Steps:

1. Unlike a Stacked Column Chart you do not want to have your dates in a Header Column in the data table.
2. Select the cells in the table and insert a 2D Scatter Chart.
3. Click the lower series in the chart, then in the pane at the right choose 'Positive Only' in the dropdown for Y Axis Error bars.
4. Choose 'Custom Values' in the 'Use' dropdown.
5. Click in the 'Positive' box, clear the value there, select column B in the 'Log' table by clicking the column letter, type -, select column B in the 'Log' table, and click the green checkmark to accept the formula (upvote to Camelot for alerting us all to the ability to do math right in some of the chart controls rather than having to set up extra columns in a table!).
6. Click the error bars in the chart and format to taste (color, width). Click each series and format Style to taste. Format the rest of the chart to taste.

SG

Hi Phodeaux,

Perhaps a Stacked Bar graph will work for you.

I know nothing about blood pressure, so here we go with some random numbers.

Also I may have systolic and diastolic the wrong way round.

Regards,

Ian.

Since when could we do math in the "value" field? That's news to me.

Honestly, I have no idea when it was added, but clearly it's an option :)

Love the idea of using error bars for the intermediate range. Nice touch.