Description
Subtract nonnegative uncertainty from height for conservativeHeight and subtract required for margin.
A clearance margin compares available vertical space with occupied space and any explicit allowance. Depths, water levels, and structure elevations must share compatible datums.
Subtract nonnegative uncertainty from height for conservativeHeight and subtract required for margin.
When to use this tool
Use Tide Height Observation Uncertainty Margin when you need a transparent component of a vertical clearance calculation.
How to use the tool and how it works
- Enter height, uncertainty, required. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read conservativeHeight, margin. Use the output convention below.
Subtract nonnegative uncertainty from height for conservativeHeight and subtract required for margin.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| height | Height | Required. Finite number. |
| uncertainty | Uncertainty | Required. Finite number; minimum 0. |
| required | Required | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| conservativeHeight | Conservative Height | Required. Finite number. |
| margin | Margin | Required. Finite number. |
{
"input": {
"height": 3,
"uncertainty": 0.2,
"required": 2.5
},
"output": {
"conservativeHeight": 2.8,
"margin": 0.2999999999999998
}
}Limitations and assumptions
- This applies a supplied one-sided allowance; it is not a tide forecast or a probabilistic safety guarantee.
- 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 current surveys, water levels, vessel data, and approved operational margins for an actual passage decision.
References
Similar or alternative tools
- Tide Height Datum Offset
Add sourceDatumElevation minus targetDatumElevation to heightAboveSource to obtain heightAboveTarget.
- Tide Observation Reference Level Shift
Add oldDatumElevation minus newDatumElevation to height.