Description
Compare firstReading+firstZero with secondReading+secondZero.
A level reading is measured relative to an origin or datum. Adding an offset can express the same supplied observation in another compatible coordinate, while changing the reference label alone does not transform a datum.
Compare firstReading+firstZero with secondReading+secondZero.
When to use this tool
Use Staff Gauge Overlap Reading Gap when you need one signed level, datum, or reference comparison.
How to use the tool and how it works
- Enter firstReading, secondReading, firstZero, secondZero, tolerance. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read elevationDifference, withinTolerance. Inspect withinTolerance before interpreting the associated values.
Compare firstReading+firstZero with secondReading+secondZero. Return first minus second elevation and an inclusive absolute-difference comparison with nonnegative tolerance.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| firstReading | First Reading | Required. Finite number. |
| secondReading | Second Reading | Required. Finite number. |
| firstZero | First Zero | Required. Finite number. |
| secondZero | Second Zero | Required. Finite number. |
| tolerance | Tolerance | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| elevationDifference | Elevation Difference | Required. Finite number. |
| withinTolerance | Within Tolerance | Required. Boolean. |
{
"input": {
"firstReading": 2,
"secondReading": 1,
"firstZero": 100,
"secondZero": 101,
"tolerance": 0.01
},
"output": {
"elevationDifference": 0,
"withinTolerance": true
}
}Limitations and assumptions
- Readings, zero elevations, and tolerance share units and compatible datums; no gauge accuracy, datum authority, or calibration acceptance standard is selected.
- 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
Verify the survey references, measurement direction, and calibration before using levels in an operational decision.
References
Similar or alternative tools
- Gauge Stage Datum Difference
Add each stage to its datum elevation, then return secondElevation minus firstElevation.
- Gauge Staff Parallax Reference Offset
Return observedReading-referenceReading and independentWaterElevation-referenceReading as correctedGaugeZero.