Stratigraphic Range Extent
Summarize observed section-position span and endpoint measurement uncertainty, not true taxon duration; positions share a caller increasing chronological/section convention.
Description
Observed stratigraphic span measures the distance between extreme occurrences.
Observed stratigraphic span measures the distance between extreme occurrences. Endpoint measurement error differs from uncertainty about the true taxon range.
Summarize observed section-position span and endpoint measurement uncertainty, not true taxon duration; positions share a caller increasing chronological/section convention.
When to use Stratigraphic Range Extent
Use this tool to summarize observed section-position span and endpoint measurement uncertainty, not true taxon duration; positions share a caller increasing chronological/section convention.
Prepare the fossil measurements or occurrence records and the chosen calibration parameters. Retain the stated coordinate, age and measurement conventions.
How to use Stratigraphic Range Extent and understand its results
- Prepare the fossil measurements or occurrence records and the chosen calibration parameters. Retain the stated coordinate, age and measurement conventions.
- Enter occurrencePositionsM, positionSigmasM using the field table and calculation rules, then run the tool.
- Read observedRangeExtentM, earliestObservedPositionM, latestObservedPositionM, independentEndpointExtentSigmaM. 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 |
|---|---|---|---|
| occurrencePositionsM | Occurrence positions m | list of number | Required |
| positionSigmasM | Position sigmas m | list of number | Required |
Use at least two aligned positions and nonnegative sigmas. Find extrema and their first matching observations, then combine their errors assuming independence.1
Paired lists must be nonempty and have equal lengths.
span = maximum position − minimum position; sigma = hypot(endpoint sigmas) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| observedRangeExtentM | Observed range extent m | number |
| earliestObservedPositionM | Earliest observed position m | number |
| latestObservedPositionM | Latest observed position m | number |
| independentEndpointExtentSigmaM | Independent endpoint extent sigma m | number |
{
"input": {
"occurrencePositionsM": [
10,
20,
30
],
"positionSigmasM": [
1,
2,
3
]
},
"output": {
"observedRangeExtentM": 20,
"earliestObservedPositionM": 10,
"latestObservedPositionM": 30,
"independentEndpointExtentSigmaM": 3.1622776601683795
}
}Limitations and assumptions
Positions need one increasing section convention; true duration and missing occurrences are not inferred.
Numbers and computed results must be finite; overflow produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Confidence Interval on Stratigraphic Range Strauss-Sadler: Calculate one-sided Strauss–Sadler endpoint extension assuming independent uniform recovery over the true stratigraphic range; not simultaneous two-endpoint coverage or corrected for heterogeneous collecting. For a complementary task, use Signor-Lipps Effect Back-Extension Estimate: Model a Signor–Lipps unobserved tail under stationary independent Poisson recovery using caller rate exposure/detection; fitted rate uncertainty and correlated sampling are excluded, not a confirmed extinction date.
References
-
Stratigraphic Range Extent — tool.io
Similar or alternative tools
- Confidence Interval on Stratigraphic Range Strauss-Sadler
Calculate one-sided Strauss–Sadler endpoint extension assuming independent uniform recovery over the true stratigraphic range; not simultaneous two-endpoint coverage or corrected for heterogeneous collecting.
- Signor-Lipps Effect Back-Extension Estimate
Model a Signor–Lipps unobserved tail under stationary independent Poisson recovery using caller rate exposure/detection; fitted rate uncertainty and correlated sampling are excluded, not a confirmed extinction date.