Description
Add east-positive deviation to compass and normalize modulo 360 for magnetic.
Bearings are circular coordinates, so zero and 360 degrees represent the same direction. Sector boundaries and true, magnetic, compass, or relative references need explicit conventions.
Add east-positive deviation to compass and normalize modulo 360 for magnetic.
When to use this tool
Use Nautical Magnetic Deviation Variation Order when you need a bearing normalization, sign correction, or sector label.
How to use the tool and how it works
- Enter compass, deviationEast, variationEast. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read magnetic, trueBearing. Use the output convention below.
Add east-positive deviation to compass and normalize modulo 360 for magnetic. Add east-positive variation and normalize again for trueBearing.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| compass | Compass | Required. Finite number. |
| deviationEast | Deviation East | Required. Finite number. |
| variationEast | Variation East | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| magnetic | Magnetic | Required. Finite number. |
| trueBearing | True Bearing | Required. Finite number. |
{
"input": {
"compass": 350,
"deviationEast": 5,
"variationEast": 10
},
"output": {
"magnetic": 355,
"trueBearing": 5
}
}Limitations and assumptions
- Corrections are signed degrees supplied for the location and vessel; the tool does not retrieve a magnetic model.
- 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 heading and magnetic information and a complete navigation process when interpreting an actual course or contact.
References
Similar or alternative tools
- Nautical: Compass Point Halfwind Label
Accept bearings from 0 through 360 degrees and normalize 360 to zero.
- Nautical: Bearing Relative To Vessel Heading
Subtract headingDegrees from bearingDegrees and normalize modulo 360.