compass
Enable an AI agent to recognise a navigational compass, assess whether its directional indication is usable, and determine appropriate observations, adjustments and uses.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise a navigational compass, assess whether its directional indication is usable, and determine appropriate observations, adjustments and uses.
A compass is a heading instrument whose directional system - typically a magnetized needle or card, a spinning gyroscope, a fluxgate, or a magnetometer - seeks and holds an azimuth reference (Earth's magnetic field, Earth's rotation, a celestial body, or a radio source) so that heading or bearing can be read against a graduated card or equivalent display.
It can be Read and record a heading or target bearing with its directional reference and operating conditions.; Align the instrument with a target, map direction or platform axis using its documented reading arrangement.; Compare repeated readings and an independent reference to assess directional reliability.; Check susceptibility to local interference by changing location or nearby equipment conditions where appropriate.; Apply or configure a documented directional correction while preserving the original reading and correction convention.; Identify a need for calibration, servicing or withdrawal from navigation use based on observed defects and applicable requirements..
Distinguishing features
Check whether the object provides a directional reference through a sensing mechanism; a printed compass rose or graduated disk alone does not establish this.
Check whether its principal task is indicating direction rather than drawing circles with hinged legs and a marking point.
Check whether an angle reading is referenced to an established direction; an ordinary protractor measures angles without independently establishing north.
Check whether the indicated quantity is direction or heading rather than geographic position, and identify the component responsible when both are provided.
Check whether the directional element actually responds under its specified operating conditions, distinguishing a functioning instrument from a decorative replica.
Scope
+ Direction-sensing mechanism and the reference direction it indicates
+ Needle, card, scale, index and sighting arrangements used to obtain a reading
+ Instrument alignment, mounting, levelling and orientation requirements
+ Calibration, directional error, interference and evidence of reading reliability
+ Physical condition and instrument-specific operating readiness
- Drawing compasses used to construct circles or transfer distances, pending registry clarification
- Maps, charts and geographic reference datasets
- Route planning, navigation decisions and journey execution
- The vehicle, vessel or other platform carrying the instrument
- Standalone position receivers and software navigation applications
Characteristics
- Direction-sensing principle
- Magnetic, gyroscopic, electronic magnetic sensing, other documented principle, unknown Determines what establishes direction and which checks, dependencies and interference sources apply.
- Indicated directional reference
- Magnetic north, true north, grid north, other documented reference, unknown Prevents treating readings expressed against different references as interchangeable.
- Direction reading
- Degrees, mils or marked cardinal divisions, with scale convention and observation time Records what was indicated without implying that scale resolution establishes accuracy.
- Reading referent
- Instrument axis, platform axis or sighted target associated with the reading Distinguishes platform heading from the bearing of an observed target.
- Scale resolution
- Smallest marked or displayed angular increment in the instrument's units Constrains how precisely a reading can be recorded.
- Reference correction configuration
- Correction type, signed angular value, convention, source and applicability; none or unknown Makes reference conversions explicit and helps prevent applying a correction twice.
- Observed directional error
- Signed angular difference from an independent reference, with test orientation and conditions Supports a use-specific judgement of reliability.
- Directional response
- Settles repeatably, oscillates, sticks, drifts, gives no indication, untested Identifies indications that may be readable but unreliable.
- Operating orientation
- Required plane or mounting attitude and documented tilt limits; unknown Determines whether the sensing element and reading arrangement are being used correctly.
- Local magnetic influence
- Suspected, observed, not detected under stated checks, unassessed, not applicable Qualifies readings that may change near magnetic materials, magnets or electrical equipment.
- Instrument condition
- Observed condition of relevant capsule, pivot, card, needle, display, markings and housing Connects specific defects to reading, handling and service decisions.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.compass-artifact
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 16 findings · 29 questions.
Direction and reference Establishes how this compass produces direction and what its indication means.
A compass reading cannot be interpreted safely without knowing its sensing principle and directional reference.
Sensing principle
Identifies the mechanism responsible for establishing direction.
Direction-producing mechanism
Record the supported instrument type and evidence identifying its sensing mechanism.
- What mechanism establishes direction in this instrument, and what observation or documentation identifies it? definition
- Does this object establish a directional reference itself or display direction supplied by another device? boundary
Reference and corrections
Captures the north reference and any transformation applied to the indication.
Indicated north and adjustment
Record the indicated reference and distinguish configured corrections from corrections applied after reading.
- Is the indication referenced to magnetic, true or grid north, or is the reference undocumented? definition
- What correction is already incorporated, and what source, date, location and sign convention support it? provenance
- What additional correction, if any, is required for the intended reference without duplicating an existing adjustment? action
Bearing acquisition Describes how instrument orientation becomes a readable heading or bearing.
Reliable sensing alone does not prevent errors from the wrong index, target alignment or scale convention.
Alignment and sighting
Connects the measured direction to the instrument axis, platform or target.
Bearing line
Record the physical or displayed features that define the direction being measured.
- Which sight, direction-of-travel arrow, lubber line or other index defines the bearing line? definition
- How is that line aligned with the target or platform axis, and is any mounting offset known? measurement
Scale and reading
Captures angular conventions and the procedure for extracting an indication.
Reading convention
Record scale units, graduation direction, reading index and supported reading precision.
- What units, numbering direction and smallest divisions does the compass use? measurement
- At which index and viewing position should the reading be taken to avoid reading the wrong end or introducing parallax? action
- Does the recorded value describe heading, target bearing or a reciprocal direction? definition
Directional reliability Captures evidence that an indication is stable and sufficiently accurate for its intended use.
A plausible compass indication can be repeatably wrong or vary with nearby influences.
Response and reference checks
Examines settling, repeatability and agreement with an independent directional reference.
Observed reading performance
Record test conditions, directional response and measured disagreement without assuming a universal acceptance tolerance.
- After changing orientation and returning to the same bearing, does the indication settle consistently, and within what observed time and spread? measurement
- What independent directional reference was used, and what errors were observed at the tested orientations? provenance
- What accuracy requirement applies to the intended use, and do the recorded checks support it? boundary
Interference and deviation
Examines external influences and installation-dependent directional error.
Environment-dependent error
Record applicable interference observations and the conditions under which compensation or deviation information remains valid.
- For a magnetic sensing instrument, does the reading change when nearby magnetic objects or electrical equipment are moved, removed or switched? measurement
- Is there a documented compensation setting or deviation record for this installation, and what changes would invalidate it? provenance
- What relocation, equipment change or specialist adjustment is supported when interference is observed? action
Operating readiness Connects compass-specific physical condition and operating dependencies to permissible use.
Tilt, mechanical obstruction, capsule defects or unmet electronic dependencies can prevent a compass from providing a usable direction.
Orientation and dependencies
Identifies the attitude, setup and resources required for a valid indication.
Valid operating setup
Record applicable levelling, balance, mounting, power and initialization requirements.
- What operating plane, tilt range or geographic balance restriction is documented for this particular compass? boundary
- What levelling, mounting, power, calibration or initialization steps must be completed before taking a reading? action
Condition and service
Examines defects affecting the directional element, enclosure or reading interface.
Compass-specific defects
Record observed faults and use instrument-specific guidance to determine their consequences.
- Are there signs of needle or card contact, sticking, capsule leakage, bubbles, displaced markings or unreadable indications? measurement
- What documented limits distinguish an acceptable observation from a defect requiring service or withdrawal from use? boundary
- Which corrective actions are permitted for the user, and which require qualified servicing followed by a directional check? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- liquid-filled marine magnetic compass (IMO/ISO Class A standard or steering compass in a binnacle; Class B for lifeboats and rescue boats)
- dry-card magnetic compass (explicitly outside ISO 25862)
- hand-bearing, prismatic and orienteering/thumb compass
- aircraft magnetic (wet) compass
- gyrocompass (true-north from Earth's rotation; electrically driven)
- gyro-magnetic and fluxgate compass
- solid-state electronic / MEMS magnetometer compass
- astrocompass and radio compass (RDF/ADF)
- Which of these kinds and varieties hold for the sense of compass this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q34735 - Item 'compass': navigational instrument indicating direction relative to Earth's magnetic field; listed subclasses include magnetic compass and gyrocompass.
- ISO vocabulary - ISO 1069:1973 - Magnetic compasses and binnacles for sea navigation - Vocabulary; terms reused by ISO 25862 and ISO 14227.
- IMO/ISO marine class - Class A | Class B - Class A = SOLAS Chapter V standard compass; Class B = IMO LSA Code lifeboat/rescue-boat compass.
- Which of these identifiers and schemes hold for the sense of compass this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- ISO 25862:2019 (Amd 1:2024) - Marine magnetic compasses, binnacles and azimuth reading devices (ISO/TC 8/SC 6)
- ISO 14227:2001 - Small craft - Magnetic compasses, hull length up to 24 m (ISO)
- ISO 1069:1973 - Magnetic compasses and binnacles for sea navigation - Vocabulary (ISO)
- IMO Resolution A.382(X) - Magnetic Compasses Carriage and Performance Standards (International Maritime Organization)
- SOLAS Chapter V Regulation 19 - heading means independent of any power supply; bearings over 360° (IMO)
- IMO Life-Saving Appliances (LSA) Code - Class B magnetic compass on lifeboats and rescue boats
- IMO Resolution MSC.86(70) Annex 2 - transmitting magnetic heading devices (IMO)
- IEC 60945 - Maritime navigation and radiocommunication equipment - general requirements and tests (IEC)
- 14 CFR 91.205 (FAR 91.205) - magnetic direction indicator as required aircraft equipment (FAA)
- Which of these standards and regulation hold for the sense of compass this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Ship standard compass in a binnacle with correctors and an azimuth-reading device, used as the power-independent heading reference required by SOLAS V.
- Steering compass (or a reflected/projected sector of the standard card) read at the helm.
- Class B compass fitted in lifeboats and rescue boats.
- Small-craft compasses on recreational and workboats up to 24 m under ISO 14227.
- Aircraft wet compass as the legally required backup when the heading indicator, vacuum system or glass-cockpit electrics fail.
- Hand-bearing, prismatic and baseplate/thumb compasses for orienteering, surveying, forestry and taking visual bearings from a boat.
- Fluxgate and solid-state compasses feeding autopilots, ECDIS, radar and electronic heading displays.
- Gyrocompass as the primary true-heading source on larger ships and high-speed craft, with the magnetic compass retained as the unpowered fallback.
- Which of these real-world use hold for the sense of compass this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- heading / azimuth on the card - 0-360, numbered every 10°, cardinals N E S W - degree
- directional error of the marine compass card (graduation, eccentricity, magnet orientation) - not more than 0.5 on any heading (IMO A.382) - degree
- compass-card diameter (ISO 25862 Class A) - ≥165 (binnacle type A1) or ≥125 (type A2) - millimetre
- horizontal geomagnetic field used in IMO period/friction tests - about 18 - microtesla
- card half-period after 40° deflection (at 18 µT) - at least 12 - second
- time to settle within ±1° of the magnetic meridian after 90° deflection - not more than 60 - second
- steering-card readability distance - 1.4 - metre
- magnetic variation (declination) - typically 0 to >20 depending on location; larger near the magnetic poles - degree
- Which of these typical measurements hold for the sense of compass this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Magnetic deviation from the host vessel's or aircraft's steel, wiring, speakers and electronics, heading-dependent and requiring a swing/adjustment and a deviation card.
- Uncorrected magnetic variation (declination) producing a systematic course error that grows with distance.
- Aircraft turning error (ANDS) and acceleration error (UNOS) while the compass is not in steady, unaccelerated flight.
- Near the magnetic poles the horizontal field is too weak; the card is sluggish or unusable.
- Local crustal anomalies, cargo changes, structural repairs or relocated equipment shifting residual deviation.
- Liquid leak, bubble, sticky pivot or worn jewel making the card lag or hang.
- Gyrocompass heading lost on power failure, plus latitude and speed errors if uncompensated.
- Treating GPS course-over-ground as compass heading; GPS fails without power or satellite signal while a magnetic compass still indicates.
- Which of these failure modes and hazards hold for the sense of compass this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Language: English compass; Spanish brújula (also compás magnético); Chinese 指南針; Norwegian kompass, with magnetkompass vs gyrokompass distinguished.
- Declination sign: easterly in much of western North America, westerly in much of eastern North America; charts carry a local compass rose.
- High-latitude (Arctic/Antarctic) practice treats the magnetic compass as unreliable and leans on gyro, GNSS or celestial methods.
- Carriage regimes differ: SOLAS Class A on most seagoing ships vs ISO 14227 for small craft ≤24 m vs FAR 91.205 for civil aircraft.
- Which of these regional variation hold for the sense of compass this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- gyrocompass - Seeks true north from Earth's rotation and gravity, needs electrical power, and is unaffected by the ship's magnetism; a magnetic compass seeks magnetic north and works unpowered.
- drawing compass (pair of compasses) - A drafting tool for circles and transfers; it has no directional system and does not indicate azimuth. Wikidata treats it as a different item from Q34735.
- pelorus - A sighting instrument for relative bearings over the horizon; it does not itself seek magnetic or true north.
- GPS/GNSS compass or course-over-ground - Heading or track is computed from satellite motion or multi-antenna baseline; it needs signal and power and does not sense the geomagnetic field.
- heading indicator / directional gyro - A gyroscopic heading display that precesses and must be reset or slaved to a magnetic or true reference; it is not itself a compass.
- magnetometer - Measures magnetic-field strength or vector; it may feed an electronic compass but does not by itself present a navigational heading card.
- transmitting magnetic heading device (TMHD) - An IMO-separate category (MSC.86(70) Annex 2) that senses and transmits magnetic heading electrically; not the same as a direct-reading liquid compass under ISO 25862.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of compass this model covers, and on what evidence? provenance
Sources
- ISO 25862:2019 Ships and marine technology - Marine magnetic compasses, binnacles and azimuth reading devices - Construction definition of a marine magnetic compass; Class A/B carriage scope; exclusion of dry-card and hand-bearing types; binnacle and azimuth-device requirements.
- ISO 14227:2001 Small craft - Magnetic compasses - Small-craft (hull length ≤24 m) magnetic-compass construction and performance; pivot-in-liquid definition; exclusion of dry-card and transmitting types; pointer to ISO 1069 vocabulary.
- IMO Resolution A.382(X) Annex II - Recommendation on Performance Standards for Magnetic Compasses - IMO definition of a magnetic compass; standard vs steering compass; card graduation, 0.5° directional-error limit, 1.4 m steering readability, damping/period tests at 18 µT.
- compass (Q34735) - Wikidata identifier; subclass of navigational instrument; also-known-as and language labels; distinction from a different 'compass' item.
- kompass - Practical kinds (orienteering, bearing, ship, fluxgate, aircraft); magnetic vs gyrocompass power distinction; Norwegian naming.
- Compasses Selection Guide: Types, Features, Applications - Industry kinds: thumb, gyro, solid-state, fluxgate, radio/ADF, prismatic hand-bearing.
- Terms in Compass Work - Specialist split into magnetic, gyro, and gyro-magnetic compasses; warning not to confuse gyrocompass with gyro-magnetic compass.
- The Magnetic Compass: Variation, Deviation, and the Turning and Acceleration Errors (ANDS/UNOS) - Variation vs deviation; aircraft turning/acceleration errors; FAR 91.205 backup role of the magnetic compass.
- Magnetic Compass Calibration: Frequency & Key Factors - Marine magnetic vs gyrocompass calibration drivers; ISO 25862/SOLAS V/IMO A.382(X) for magnetic, IMO A.821(19) for gyro.
- Magnetic deviation - Deviation as local ferrous/electrical error distinct from declination/variation; comparison with gyro, astronomical and satellite heading.
- SOLAS Chapter V - Magnetic Compasses (Regulation 19 guidance) - Carriage of a heading means independent of power supply; pelorus/bearings over 360°; A.382(X) and TMHD MSC.86(70) performance standards.
What the second pass must settle
- Does vr.tr.compass denote navigational compasses exclusively, or does the registry intend to include drawing compasses?
- Should magnetic, gyroscopic and satellite-based heading instruments share this model, or should existing neighbouring models own some of these types?
- Does an existing Vercy world model already own this concept and require this registry entry to link to it?
- Which authoritative instrument manuals or standards establish applicable checks and acceptance limits for each supported compass type?
- How should the model distinguish magnetic declination, installation deviation, grid conversion and automatic corrections across different reading interfaces?