Sankey Chart Missing or Negative Values: What Happens
A blank, negative or non-numeric amount cannot be drawn as a ribbon. See how the editor treats it, when it falls back to equal-width ribbons, and how to fix the data.
Ribbon width comes from the amount. A blank, negative or non-numeric amount has no width, so the editor does not draw a quantity for it and flags the flow.
A missing, negative or unreadable amount is treated as no amount. The flow is flagged with a warning rather than guessed at, and the totals of the nodes it touches are not checked, because their sums would be partial.
If every flow is missing its amount, the chart falls back to ribbons of equal width, which shows the connections without any quantity. The example shows a complete data set you can break and fix.
What counts as missing
A blank cell, text that is not a number, and a negative number all end up as no amount. Zero is a real amount of zero, and the flow has no width.
- Blank: no amount, flagged.
- Text such as n/a: no amount, flagged.
- Negative: no amount, flagged.
- Zero: valid, drawn with no width.
Fixing it
Find the flagged flow in the sheet and enter a positive number. If the amount is genuinely a reversal, such as a refund, model it as a separate flow in the opposite direction instead of a negative number.
Equal-width ribbons
If no flow has an amount, every ribbon is drawn the same width. That is useful for sketching the structure first and adding the numbers later, but it should not be read as a quantity.
Key points
- 100 orders enter; 90 are shipped and 10 cancelled.
- Of the 90 shipped, 9 are returned and 81 are kept.
- With a blank amount on any of these flows, that flow is flagged and the balance of the nodes it touches is not checked.
- The figures are invented.
The example’s data
Invented counts, complete and balanced.
| From | To | Amount (orders) |
|---|---|---|
| Orders | Shipped | 90 |
| Orders | Cancelled | 10 |
| Shipped | Returned | 9 |
| Shipped | Kept | 81 |
The same data as CSV
source,target,value
Orders,Shipped,90
Orders,Cancelled,10
Shipped,Returned,9
Shipped,Kept,81How it works
Find the flagged flows
They carry a warning in the sheet.
Enter a positive number for each
Use the same unit as the rest.
Model reversals as flows
A refund is a flow back to a node, not a negative number.
Check the balance
Once every amount is present the nodes are checked again.
Frequently asked questions
Can I leave amounts blank while drafting?
Yes. Blank flows are flagged but drawn as connections, and if all are blank the chart uses equal-width ribbons.
Why is a node not warned when its numbers look wrong?
A node with a missing amount on any of its flows is skipped by the balance check, because its sums are incomplete.
Edit this orders Sankey
Open the example as your own chart and try blanking an amount to see the flag.
