Regional Reference Period Share Tool

Description

Return reference-period share after excluded overlap duration.

Regional records connect place labels, language coverage, source vintages, calendar offsets and historical units. A literal label or supplied year offset can organize metadata without resolving changes in borders, calendar systems or naming authority. Unknown and ambiguous values must retain their explicit flags.

Return reference-period share after excluded overlap duration.

When to use this tool

Use Regional Reference Period Share when checking the stated regional record, period, hierarchy or text convention.

How to use the tool and how it works

Enter observationStart, observationEnd, referenceStart, referenceEnd, excludedDuration. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read overlap, supportedOverlap, referenceShare. Use the output convention below.

Return reference-period share after excluded overlap duration. Require ordered observation/reference intervals with positive reference width and nonnegative exclusion <= overlap; overlap is continuous interval intersection, supportedOverlap subtracts exclusion.^[1]

Input field	Meaning and units	Accepted input
observationStart	Observation Start	Required. Finite number.
observationEnd	Observation End	Required. Finite number.
referenceStart	Reference Start	Required. Finite number.
referenceEnd	Reference End	Required. Finite number.
excludedDuration	Excluded Duration	Required. Finite number; minimum 0.

Output field	Interpretation	Returned shape
overlap	Overlap	Required. Finite number.
supportedOverlap	Supported Overlap	Required. Finite number.
referenceShare	Reference Share	Required. Finite number.

json

{
  "input": {
    "observationStart": 0,
    "observationEnd": 10,
    "referenceStart": 5,
    "referenceEnd": 15,
    "excludedDuration": 1
  },
  "output": {
    "overlap": 5,
    "supportedOverlap": 4,
    "referenceShare": 0.4
  }
}

Limitations and assumptions

Exclusions are supplied and no inclusive endpoint increment is added; actual observation quality or historical coverage is not verified.
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 sources, applicable calendar and historical naming/measurement authorities for geographic or historical interpretation.

References

Calculation and input contract: area-studies/regional-reference-period-share — tool.io

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