Ambient Monitor Collocation Relative Gap Tool

Description

Return signedDifference = first-second and relativeDifference = 2*(first-second)/(abs(first)+abs(second)).

Environmental measurements can require background subtraction, recovery correction, calibration or a common reference basis. Corrected values can be signed; a numerical correction is separate from detection, analytical validity and health interpretation.

Return signedDifference = first-second and relativeDifference = 2*(first-second)/(abs(first)+abs(second)).

When to use this tool

Use Ambient Monitor Collocation Relative Gap when checking a supplied measurement correction, comparison or calibration term.

How to use the tool and how it works

Enter first, second. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read signedDifference, relativeDifference. Use the output convention below.

Require abs(first)+abs(second) > 0. Return signedDifference = first-second and relativeDifference = 2*(first-second)/(abs(first)+abs(second)). Both readings share one unit; relativeDifference is a signed fraction and is not multiplied by 100.^[1]

Input field	Meaning and units	Accepted input
first	First	Required. Finite number.
second	Second	Required. Finite number.

Output field	Interpretation	Returned shape
signedDifference	Signed Difference	Required. Finite number.
relativeDifference	Signed symmetric fraction 2*(first-second)/(abs(first)+abs(second)); not a percent.	Required. Finite number.

json

{
  "input": {
    "first": 12,
    "second": 8
  },
  "output": {
    "signedDifference": 4,
    "relativeDifference": 0.4
  }
}

Limitations and assumptions

Both zero readings are rejected. This signed symmetric gap differs from an absolute relative percent difference; negative readings remain permitted, and the tool does not select a collocation acceptance criterion.
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 the relevant analytical method, quality-control records and uncertainty model before classifying a corrected measurement.

References

Calculation and input contract: environmental-science/ambient-monitor-collocation-relative-gap — tool.io

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