Date Span Open vs Closed Range Classifier
Classify explicit known/unknown year endpoints in an archival descriptive range, distinct from ISO interval duration validation; -1 means unknown, not an actual year.
Description
An archival descriptive date span can have one or both endpoints unknown.
An archival descriptive date span can have one or both endpoints unknown. Unknown endpoints need an explicit marker so they are not mistaken for actual historical years.1
Classify explicit known/unknown year endpoints in an archival descriptive range, distinct from ISO interval duration validation; -1 means unknown, not an actual year.
When to use Date Span Open vs Closed Range Classifier
Use this tool to classify explicit known/unknown year endpoints in an archival descriptive range, distinct from ISO interval duration validation; -1 means unknown, not an actual year.
Prepare the inventory, measurements or policy dates for the collection and reporting period. Confirm units, record order and any independently established thresholds or permissions.
How to use Date Span Open vs Closed Range Classifier and understand its results
- Prepare the inventory, measurements or policy dates for the collection and reporting period. Confirm units, record order and any independently established thresholds or permissions.
- Enter yearSpan using the field table and calculation rules, then run the tool.
- Read spanKind, knownStartYear, knownEndYear. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| yearSpan | Year span | string | Required |
Enter exact slash-separated endpoints, each either .. or a four-digit year from 1000 to 9999. Known endpoints must be chronological. The tool returns the span kind and known years; −1 is used for each unknown endpoint. Whitespace, partial dates and other interval syntax are rejected.
YYYY/YYYY = closed; ../YYYY = open-start; YYYY/.. = open-end; ../.. = both-open Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| spanKind | Span kind | string |
| knownStartYear | Known start year | number |
| knownEndYear | Known end year | number |
{
"input": {
"yearSpan": "1900/.."
},
"output": {
"spanKind": "open-end",
"knownStartYear": 1900,
"knownEndYear": -1
}
}Limitations and assumptions
Open means an unknown endpoint under this descriptive syntax, not a mathematical boundary-exclusion rule. No duration, inferred year or calendar-date validity is calculated.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Bulk Date Dominant Range Extractor: Find earliest tied shortest contiguous bucket span meeting caller dated-item coverage, with at most 128² comparisons; undated records and within-bucket temporal precision are not invented. For a complementary task, use Access Restriction Closure Period End Year Calculator: Resolve explicit whole-year closure policy including closure through final year and opening next year; no automatic privacy law, partial-date period or access-rights determination.
References
Similar or alternative tools
- Bulk Date Dominant Range Extractor
Find earliest tied shortest contiguous bucket span meeting caller dated-item coverage, with at most 128² comparisons; undated records and within-bucket temporal precision are not invented.
- Access Restriction Closure Period End Year Calculator
Resolve explicit whole-year closure policy including closure through final year and opening next year; no automatic privacy law, partial-date period or access-rights determination.