Geology Wentworth Phi To Mm Calculator

Invert phi BIN intervals to diameter intervals, decreasing mapping reverses bounds; not arithmetic mean diameter from inverted mean phi. Caller independently establishes matching units, evidence, method edition and applicability; output is not compliance, diagnosis, work-safety approval, geological identity or validated hazard prediction.

Description

The phi grain-size scale is logarithmic, with increasing phi corresponding to decreasing diameter.

The phi grain-size scale is logarithmic, with increasing phi corresponding to decreasing diameter.^[1]

Transforming an interval therefore reverses which phi endpoint gives the lower diameter in millimeters. Use this tool to calculate wentworth phi to mm from the supplied measurements and assumptions.

When to use Geology Wentworth Phi To Mm Calculator

Use this tool to calculate wentworth phi to mm from the supplied measurements and assumptions. Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.

How to use Geology Wentworth Phi To Mm Calculator and understand its results

Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
Enter phiBinLower, phiBinUpper, using the field meanings and rules below, then run the tool.
Read diameterLowerMm, diameterUpperMm. Interpret the fields using their units, signs and evidence conventions below.
If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.

Input field	Meaning	Value type	Requirement
phiBinLower	Phi bin lower	list of number	Required
phiBinUpper	Phi bin upper	list of number	Required

Enter nonempty aligned lower and upper phi endpoints within −40 through 40, requiring lower≤upper for every bin. Transform each endpoint using diameterMm=2^(−phi). Reverse endpoint order to return the increasing diameter interval; equal endpoints yield equal diameters.

diameterLowerMm=2^(−phiUpper); diameterUpperMm=2^(−phiLower)

Use the exact units, boundary rules, ordering and missing-evidence conventions above.

Output field	Meaning	Value type
diameterLowerMm	Diameter Lower Mm; follow the units, sign, ordering and evidence convention stated above	list of number
diameterUpperMm	Diameter Upper Mm; follow the units, sign, ordering and evidence convention stated above	list of number

json

{
  "input": {
    "phiBinLower": [
      -1,
      0
    ],
    "phiBinUpper": [
      0,
      1
    ]
  },
  "output": {
    "diameterLowerMm": [
      1,
      0.5
    ],
    "diameterUpperMm": [
      2,
      1
    ]
  }
}

Limitations and assumptions

Transforming an interval therefore reverses which phi endpoint gives the lower diameter in millimeters. Interpretation depends on the units, sampling scope and exact model described above.

All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.

Alternative or Complementary methods

Use Geology Wentworth Grain Size Phi Calculator for this related task: A phi value is the negative base-two logarithm of grain diameter measured in millimeters.

Use Geology Sorting Coefficient Trask Calculator when its separate inputs and assumptions fit the question: The Trask sorting coefficient compares two diameter percentiles through their ratio.

References

Geology Wentworth Phi To Mm Calculator — tool.io

Similar or alternative tools

Geology Wentworth Grain Size Phi Calculator
A phi value is the negative base-two logarithm of grain diameter measured in millimeters.
Geology Sorting Coefficient Trask Calculator
The Trask sorting coefficient compares two diameter percentiles through their ratio.