Old instruments
Line of Position
Direct answer
Line of Position is a line on which the observer is estimated to lie according to one navigation observation.
Line of Position is a geographic position constraint used in historical astronomy, timekeeping, or navigation.
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At a glance
- Found in
- Historical Almanacs & Instruments
- Related
- Intercept Method, Marcq Saint-Hilaire Method, Celestial Position Fix, Running Fix
Line of Position is a geographic position constraint used in historical astronomy, timekeeping, or navigation.
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Why Line of Position matters
Line of Position matters because one observation narrows location to a locus while two or more suitable observations can determine a fix.
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Line of Position in practice: an example
A celestial altitude produces a local line approximately perpendicular to the body's azimuth.
Where readings of Line of Position go wrong
A line is not a point, and nearly parallel lines create a weak intersection with large uncertainty.
Sources and editorial method
Research references used for this entry include:
- National Geospatial-Intelligence Agency: The American Practical Navigator - Official modern reference for navigation principles, celestial observations, sight reduction, and navigational tables.
- Source
- The Great Almanac Dictionary
- Category
- Historical Almanacs & Instruments
- Last updated
- 2026-09-26
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More in Historical Almanacs & Instruments
- Meridian Circle
- Orrery
- Repeating Circle
- Sun Sight
- Astronomical Quadrant
- Computed Altitude
- Equinoctial Ring Dial
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Common questions
What is Line of Position?
Line of Position is a line on which the observer is estimated to lie according to one navigation observation.
What do people get wrong about Line of Position?
A line is not a point, and nearly parallel lines create a weak intersection with large uncertainty.
Why does Line of Position matter?
Line of Position matters because one observation narrows location to a locus while two or more suitable observations can determine a fix.
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