Part of it is an Apples and Oranges issue. The rest may come from Numbers trying to solve that issue.
To make any sense, a stacked bar chart, essentially a chart is which two or more bars are stacked, one atop the other, or, as in this case, laid end to end, needs both bars to be displaying the same type of data.
Here, the bright green bar is to display a duration value, days, but the pale bar is provided with a Date and Time value, a value marking a single instant in the flow of time.
Revise your table to provide two duration values, and you should be good to go. Still a bit of a slog, though, as you'll need to add a rotated text box to hold the date labels along the x axis, and may need to add a 'frame' around the chart.
Table:
Row 1 must be a Header row.
Column A must be a header column.
A1 contains the date on which the project starts. This is used in all calculations in column D of the table
The rest of column A contains the labels to be attached o each job/task in the project.
Column B contains the start date of each task.
Column C contains the end date of each task.
Column D contains the formula below, which calculates the number of days from the project start date to the task start date. (length of first bar)
D2: DUR2DAYS(B2−$A$1)
Fill down to the end of column D.
Column E contains the formula below, which calculates the number of days from each task start date to the task end date. (length of second bar)
E2: DUR2DAYS(C2−B2)
Fill down to end of column E.
In the table, select column D for the first set of values to be charted, then select column E for the second set.
The bar colours came up for me as bright blue and glowing green (shown).
Click the first bar, visible in the lower example, then in the Style menu choose No Fill from the pop-up menu labeled 'Fill'.
Click off the chart to deselect the bar (and the chart), then click once of the chart to re-select it. In the inspector, choose Axis, then Value (x) axis.
Set the value labels to Same as Source data, and rotate the labels to vertical left.
Use the stepper in Axis Scale > Steps to get an integer label on each step marker. (Best I could get was 0, 10, 20…).
Add one minor step to get markers at five day intervals.
If you're OK with the axis being marked in numbers of days since start, stop there.
If you want Date values, carry on…
Click on the Table to select it, then click once on the column control (at the right end of the column reference tabs) to add a column to the table.
Click on the new column's reference tab to select it, then click and hold about midway between the letter (F) and the left edge of the tab.After a brief wait, the tab and its column will 'rise' from the table. Drag right to move the column away from the rest of the table. When it separates, drag it to a convenient location, then release the mouse button to drop it onto the canvas.
In cell A2 of the new, single column table, enter the starting date shown in A1 of the main table. In A3, type= to open the formula browser, then enter the formula A2+5 (this assumes you'll have a 10 day difference between the numbers along the axis). Click the green check to confirm the formula and close the browser.
Add as many rows as needed to get to the last date on the chart, then fill the formula down fro A3 to the end of the column.
Copy the cells containing the dates, then click the text button to open a text box. Drag it to a convenient location, then click in the box, go to the edit menu and choose Paste and match style.
With the box selected, but not the text, go to the Arrange inspector panel and set rotate to 90°
Change to the Style section and change No Fill to Color fill and choose White.
You may have to do some adjustments to the line spacing in the box or to the width of the chart to get an acceptable alignment of the labels in the box with the date marker lines on the chart.
Place the box so that Jan 1 is at the left most number (0), then use as far right as possible to match with the correct marker on the chart axis.
When satisfied. nudge the box upward to cover the numbers as shown above.
Note on the Border:
The border I used is a rectangular shape with no fill, thin borders, and no shadow placed behind the chart.
If you prefer it to the border placed by the checkbox in the inspector, roll your own. If you OK with the 'native' border, go with that one. I used the bigger one mostly because I'd already taken the screen shot when I found the checkbox. :-)
Regards,
Barry
