Description
Intersect an ordered tenure interval with a positive-width reference interval.
Archival records often contain bounded dates, editions, and source identifiers. Arithmetic on supplied coordinates can check consistency while leaving historical interpretation and authenticity unresolved.
Intersect an ordered tenure interval with a positive-width reference interval.
When to use this tool
Use Historic Public Unit Tenure Share when you need a precise date-span or source-record bookkeeping step.
How to use the tool and how it works
- Enter startYear, endYear, referenceStart, referenceEnd. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read overlapYears, referenceYears, share. Use the output convention below.
Intersect an ordered tenure interval with a positive-width reference interval. Divide overlapYears by referenceYears.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| startYear | Start Year | Required. Safe integer. |
| endYear | End Year | Required. Safe integer. |
| referenceStart | Reference Start | Required. Safe integer. |
| referenceEnd | Reference End | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| overlapYears | Overlap Years | Required. Safe integer. |
| referenceYears | Reference Years | Required. Safe integer. |
| share | Dimensionless fraction under the stated denominator policy. | Required. Finite number. |
{
"input": {
"startYear": 1900,
"endYear": 1920,
"referenceStart": 1910,
"referenceEnd": 1950
},
"output": {
"overlapYears": 10,
"referenceYears": 40,
"share": 0.25
}
}Limitations and assumptions
- The calculation uses continuous year differences, not inclusive year counts or archival verification.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Consult the original catalog and documented calendar or dating convention when historical interpretation matters.
References
Similar or alternative tools
- Public Archive Unit Date Overlap
Return max(0, min(end values) - max(start values)).
- Public Era Date Precision Width
Subtract earliestCoordinate from latestCoordinate and add positive quantum only when endpointsInclusive is true.