Geology QAPF Classification Lookup

Independently normalized same-triangle QAPF coordinates and verified polygons; caller resolves quartz/feldspathoid conflict and triangle basis. Shared boundaries and overlaps retained; polygons must be simple non-self-intersecting. 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

QAPF classification uses independently determined mineral proportions and a specified classification diagram.

QAPF classification uses independently determined mineral proportions and a specified classification diagram.^[1]

This tool receives already established two-dimensional coordinates and polygons rather than deriving mineral fractions from a chemical analysis. Use this tool to calculate qapf classification lookup from the supplied measurements and assumptions.

When to use Geology QAPF Classification Lookup

Use this tool to calculate qapf classification lookup 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 QAPF Classification Lookup and understand its results

Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
Enter observedQapfX, observedQapfY, callerQapfClassIds, callerQapfVertices, using the field meanings and rules below, then run the tool.
Read matchingClasses. 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
observedQapfX	Observed qapf x	number	Required
observedQapfY	Observed qapf y	number	Required
callerQapfClassIds	Caller qapf class ids	list of string	Required
callerQapfVertices	Caller qapf vertices	list of list of number	Required

Enter finite point coordinates, unique class IDs and a vertex matrix whose rows are [zero-based class index, x, y]. Use at most 64 classes and 128 total vertices. Group vertices by class in the supplied order; each polygon needs at least three distinct vertices and nonzero area. A repeated closing endpoint is removed; other repeated vertices, intersecting nonadjacent edges and invalid integer class indices fail. The implementation applies an even–odd ray-crossing test and includes points exactly on a segment. Return every containing class in caller order, so overlapping polygons or shared boundaries may yield several classes; no match yields an empty list. Boundaries and coordinate preprocessing are independently supplied.

matches={class_i:point is inside polygon_i or exactly on its boundary}

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

Output field	Meaning	Value type
matchingClasses	Matching Classes; follow the units, sign, ordering and evidence convention stated above	list of string

json

{
  "input": {
    "observedQapfX": 0.5,
    "observedQapfY": 0.5,
    "callerQapfClassIds": [
      "a",
      "b"
    ],
    "callerQapfVertices": [
      [
        0,
        0,
        0
      ],
      [
        0,
        1,
        0
      ],
      [
        0,
        1,
        1
      ],
      [
        0,
        0,
        1
      ],
      [
        1,
        0.5,
        0.5
      ],
      [
        1,
        2,
        0.5
      ],
      [
        1,
        2,
        2
      ],
      [
        1,
        0.5,
        2
      ]
    ]
  },
  "output": {
    "matchingClasses": [
      "a",
      "b"
    ]
  }
}

Limitations and assumptions

This tool receives already established two-dimensional coordinates and polygons rather than deriving mineral fractions from a chemical analysis. 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 TAS Classification Lookup for this related task: A total-alkali–silica classification uses composition coordinates and an adopted set of class boundaries.

Use Geology Folk Sandstone Classification Lookup when its separate inputs and assumptions fit the question: A Folk sandstone classification depends on independently identified components and the adopted diagram convention.

References

Geology QAPF Classification Lookup — tool.io

Similar or alternative tools

Geology TAS Classification Lookup
A total-alkali–silica classification uses composition coordinates and an adopted set of class boundaries.
Geology Folk Sandstone Classification Lookup
A Folk sandstone classification depends on independently identified components and the adopted diagram convention.