Raster Pixel Ground Support Share Tool

Description

validGroundArea sums valid pixels; observedGroundArea additionally requires observed; share is their ratio when positive, otherwise zero with defined = false.

Spatial and grain-size summaries depend on area, bin width, scale and boundary conventions. Area-weighted coverage differs from pixel counts, while density per transformed grain-size unit differs from a raw bin fraction.

validGroundArea sums valid pixels; observedGroundArea additionally requires observed; share is their ratio when positive, otherwise zero with defined = false.

When to use this tool

Use Raster Pixel Ground Support Share when checking a supplied spatial, grain-bin or ground-support quantity.

How to use the tool and how it works

Enter pixelAreas, groundValid, observed. Keep parallel arrays aligned. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read validGroundArea, observedGroundArea, share, defined. Inspect defined before interpreting the associated values.

Require equally long nonnegative pixelAreas, groundValid and observed arrays. validGroundArea sums valid pixels; observedGroundArea additionally requires observed; share is their ratio when positive, otherwise zero with defined = false.^[1]

Input field	Meaning and units	Accepted input
pixelAreas	Pixel Areas	Required. Array of finite number; minimum 0; maximum items 256.
groundValid	Ground Valid	Required. Array of boolean; maximum items 256.
observed	Position-aligned flags specifying which records are observed.	Required. Array of boolean; maximum items 256.

Output field	Interpretation	Returned shape
validGroundArea	Valid Ground Area	Required. Finite number.
observedGroundArea	Observed Ground Area	Required. Finite number.
share	Dimensionless selected contribution divided by the stated total; not percent.	Required. Finite number.
defined	Whether the stated denominator has positive support; read this before interpreting a zero placeholder.	Required. Boolean.

json

{
  "input": {
    "pixelAreas": [
      2,
      3,
      5
    ],
    "groundValid": [
      true,
      true,
      false
    ],
    "observed": [
      true,
      false,
      true
    ]
  },
  "output": {
    "validGroundArea": 5,
    "observedGroundArea": 2,
    "share": 0.4,
    "defined": true
  }
}

Limitations and assumptions

This is area-weighted observation support, not a pixel-count percentage. Flags, georeferencing, overlap and ground-truth accuracy are supplied rather than 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

Use suitable mapping, grain-size and sampling methods for complete spatial distributions and geological interpretation.

References

Calculation and input contract: earth-science/raster-pixel-ground-support-share — tool.io

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