Soil Phosphorus Anomaly Test Tool

Standardize soil phosphorus against caller matched-method reference samples and apply a strict upper anomaly cutoff; anomalies do not independently establish occupation or human origin.

Description

A soil-phosphorus anomaly compares an observation with a matched background distribution.

A soil-phosphorus anomaly compares an observation with a matched background distribution. Standardization expresses the difference in units of observed reference variation.^[1]

Standardize soil phosphorus against caller matched-method reference samples and apply a strict upper anomaly cutoff; anomalies do not independently establish occupation or human origin.

When to use Soil Phosphorus Anomaly Test Tool

Use this tool to standardize soil phosphorus against caller matched-method reference samples and apply a strict upper anomaly cutoff; anomalies do not independently establish occupation or human origin.

Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.

How to use Soil Phosphorus Anomaly Test Tool and understand its results

Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.
Enter samplePhosphorusMgPerKg, referencePhosphorusMgPerKg, callerMaximumStandardizedDifference using the field table and calculation rules, then run the tool.
Read referenceMeanMgPerKg, referenceSampleSdMgPerKg, sampleStandardizedDifferences, aboveCallerAnomalyFlags. 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
samplePhosphorusMgPerKg	Sample phosphorus mg per kg	list of number	Required
referencePhosphorusMgPerKg	Reference phosphorus mg per kg	list of number	Required
callerMaximumStandardizedDifference	Caller maximum standardized difference	number	Required

Enter nonnegative sample and reference concentrations in mg/kg and a positive upper cutoff. At least two reference values with positive sample variance are required. Calculate the reference mean and n−1 sample SD, then each signed standardized difference and strict upper-exceedance flag. An empty sample list returns empty screening results.

Sample variance requires at least two samples and uses the n−1 denominator.

z_i = (sample_i−referenceMean)/referenceSampleSD; flag = z_i>caller cutoff

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
referenceMeanMgPerKg	Reference mean mg per kg	number
referenceSampleSdMgPerKg	Reference sample sd mg per kg	number
sampleStandardizedDifferences	Sample standardized differences	list of number
aboveCallerAnomalyFlags	Above caller anomaly flags	list of number

json

{
  "input": {
    "samplePhosphorusMgPerKg": [
      20,
      30
    ],
    "referencePhosphorusMgPerKg": [
      10,
      20,
      30
    ],
    "callerMaximumStandardizedDifference": 1
  },
  "output": {
    "referenceMeanMgPerKg": 20,
    "referenceSampleSdMgPerKg": 10,
    "sampleStandardizedDifferences": [
      0,
      1
    ],
    "aboveCallerAnomalyFlags": [
      0,
      0
    ]
  }
}

Limitations and assumptions

Analytical method and reference comparability must be established separately. A phosphorus anomaly does not prove occupation or human origin. Measurement and background uncertainty are not propagated beyond the reference spread.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. 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 Magnetic Susceptibility Floor Anomaly Tool: Compare paired same-basis floor/background susceptibility with instrument offset and caller enhancement policy; signed differences remain and enhancement is not proof of burning or a buried floor. For a complementary task, use GPR Reflection Amplitude Feature Tool: Screen caller selected GPR reflection/noise amplitude windows using RMS SNR; assumes matched gain/processing and does not identify feature material, burial or archaeological origin.

References

Soil Phosphorus Anomaly Test Tool — tool.io

Similar or alternative tools

Magnetic Susceptibility Floor Anomaly Tool
Compare paired same-basis floor/background susceptibility with instrument offset and caller enhancement policy; signed differences remain and enhancement is not proof of burning or a buried floor.
GPR Reflection Amplitude Feature Tool
Screen caller selected GPR reflection/noise amplitude windows using RMS SNR; assumes matched gain/processing and does not identify feature material, burial or archaeological origin.