Description
Add oldDatumElevation minus newDatumElevation to height.
A vertical datum supplies the zero level from which a height or depth is measured. Changing that zero shifts the reported number without moving the physical surface.
Add oldDatumElevation minus newDatumElevation to height.
When to use this tool
Use Tide Observation Reference Level Shift when you need a height conversion with a known datum offset.
How to use the tool and how it works
- Enter height, oldDatumElevation, newDatumElevation. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read height. Use the output convention below.
Add oldDatumElevation minus newDatumElevation to height.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| height | Height | Required. Finite number. |
| oldDatumElevation | Old Datum Elevation | Required. Finite number. |
| newDatumElevation | New Datum Elevation | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| height | Height | Required. Finite number. |
json
{
"input": {
"height": 3,
"oldDatumElevation": 2,
"newDatumElevation": 4
},
"output": {
"height": 1
}
}Limitations and assumptions
- All elevations must use the same reference and length unit; datum offsets are supplied rather than looked up.
- 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
Obtain location-specific datum relationships and uncertainty from the responsible survey or hydrographic authority.
References
Similar or alternative tools
- Tide Height Datum Offset
Add sourceDatumElevation minus targetDatumElevation to heightAboveSource to obtain heightAboveTarget.
- Sounding Datum Uncertainty Sign
Subtract tideAboveDatum from measuredDepth for datumDepth.