A dimension is only worth as much as the document behind it. This page sets out where the figures on Playfield Atlas come from, how they are labeled, how units are handled, how the diagrams are drawn, and how often everything is checked again.
Where a measurement comes from
Every figure starts at the current rulebook or facility handbook of the governing body for that sport. Not a summary of it, not a supplier’s product page, and not another reference site. When the primary document is read, four things are recorded: the organization, the document, the edition, and the date it was consulted.
Those four items travel with the figure to the page. The Key measurements block on each guide links to the source document so you can read the original wording rather than take our summary of it. Where a governing body publishes both a rulebook and a separate facilities or equipment handbook, the one that actually governs the figure is the one cited.
The four kinds of figure
Not every number in a guide has the same weight. Each one carries one of four labels, and the label is shown next to the figure in the Key measurements block.
| Label | What it means | Example |
|---|---|---|
| Official rule | The governing body states this figure in its rules. Play outside it is not play under those rules. | Net height at the center of a badminton court, set in the BWF Laws of Badminton. |
| Recommendation | The governing body publishes the figure as advice or good practice, not as a condition of play. | Run-back and side clearance advised around a tennis court for recreational use. |
| Derived calculation | Arithmetic we performed on official figures. The inputs are cited; the result is not in any rulebook. | A FIBA court is 28 m by 15 m, so the playing area is 420 m² — a number the rules never state. |
| Common practice | What is widely done in clubs, schools or backyards. No document requires it. | The lowered rim height often used for young children on a home basketball hoop. |
Units and rounding
The governing figure is published in the unit the rule uses. Tennis is written in feet and inches by the ITF; basketball is written in meters by FIBA. Reversing that would quietly turn a rule into a conversion.
The other unit is calculated once, from the governing figure, and rounded to a precision the rule actually supports. A tennis court 78 feet long is 23.77 m, not 23.7744 m. A badminton net 1.524 m high is 5 feet, not 5.0000 feet. Extra decimals look like accuracy and are not: they imply a tolerance the rulebook never claimed, and they will not survive contact with a tape measure or a line-marking machine.
Diagrams
Every diagram is drawn in-house as SVG, from the written rule, using the same figures shown in the Key measurements block. Federation artwork is never traced, copied or redrawn from an image. Drawing from the text is slower, and it has a useful side effect: a rule that cannot be drawn without guessing is a rule we have not yet understood well enough to publish.
Verification and re-checking
Each guide shows a verification date: the day its figures were last compared against the source documents. Governing bodies amend their rules, renumber clauses and reissue handbooks. A figure that was correct two editions ago can be wrong today, so a measurement is only as good as its date.
When a source is reissued, the guide is read against the new edition, the citation is updated, and the verification date moves. If a figure changed, the change is described rather than silently overwritten.
What we do not do
- We do not average competing sources. When two documents disagree, both are named and the scope of each is stated. A midpoint would belong to neither.
- We do not publish a number we cannot attribute. A figure with no document behind it is left out, and the gap is described instead.
- We do not present a recommendation as a rule, or common practice as either. The label stays with the figure wherever it appears.
If a figure cannot be tied to a document, it does not go on the site — an omission is easier to correct than a wrong number in circulation.
When we get it wrong
This method reduces errors; it does not remove them. If a figure here disagrees with the document it cites, or the document has been superseded, tell us which page, which figure and which edition you are reading. Corrections are handled in the open, and the verification date moves when the fix lands.