How do I change the x-axis from "Column A" to "Column C" in Numbers?

You're so close.

Two things will help here. First, you've done the hard work of converting the text to a date field. That's key.

By default, Numbers will use the header row and column for the axis labels. Since you added the calculated DATE() in column C, Numbers didn't pick that up. It would have been easier if you'd created a new column A and put the dates there, but even then, that's not the key.

I'm guessing that you created a Line Chart from your data. Despite the valid DATE()s, numbers will treat all rows as equal and NOT create a time-based chart.

The correct chart to use is a Scatter chart. This is the only chart that honors gaps in timelines.

Now, you might have tried that and didn't get the result you wanted, but that's because Numbers' defaults don't always make sense and you have to do a little tweaking.

I created a dummy table (with your calculated dates in column C), selected the Date, Diastolic and Systolic columns, clicked Chart -> Scatter and this is what I got by default:

Pretty close - at least the values match their dates over time. What's missing is the lines, but that's because scatter charts don't use them by default.

You need to select the chart (click anywhere) and check the Inspector for Connection Lines and set it to Straight:

That should get you what you want (I hope):

Thank goodness that's just dummy data :)

That's not the case at all. He's the chart recreated with the calculated date in column A:

It's certainly easier to do with adjacent columns since you can just drag across them to select, but it's not a requirement.

Oddly, in testing this, I did get a graph similar to yours, but I can't recreate it now. Either way, the key is in the Series Inspector:

When you click on one of the data points, the Series inspector will show you the settings. In this case you can see that the X values are taken from column A. It sounds like this is getting picked up incorrectly, but it's fixable - just delete the Table 1::A (or whatever reference is in there), then click on the column heading you want this series to use.

You may need to repeat this for each series.

Hi Joe,

A scatter plot requires all data to be in body cells, not header cells (Labels of course are in a header row). In your first screen shot it seems that the calculated dates are in a header column. I'm thinking that all the shuffling you did moved those dates to body cells. Possible?

Regards,

Ian.