{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.longitude","code":"thing-q36477","url":"https://ver.cy/models/thing/q36477/","name":"longitude","alternateNames":["east longitude","ZGD"],"kind":"thing","status":"published","version":"0.2.0-wave.4","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"The geographic coordinate that specifies east-west position on the Earth as an angle from the prime meridian at Greenwich, ranging from 0 to 180 degrees east and west, so that east longitude covers the Eastern Hemisphere, measured historically by chronometers and lunar distances and today by satellite positioning, and paired with latitude to locate any point; longitude also appears in celestial and planetary coordinate systems.","purpose":"Let an agent explain longitude and how it is defined and measured, relay history, conventions and reference meridians from geodesy and navigation sources, describe uses in mapping and time zones, and distinguish longitude from latitude, from local time and from celestial longitude.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Angular east-west coordinate","Arbitrary prime meridian","Time relation","Historically hard to measure"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What longitude is.","layers":[{"id":"definition","name":"Definition","description":"Definition.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"What is longitude, how is it measured from the prime meridian, and how does it differ from latitude?","kind":"definition"},{"text":"Is the question about geographic longitude, time, celestial coordinates or history?","kind":"boundary"}]}]},{"id":"conventions","name":"Conventions","description":"Conventions.","findings":[{"id":"conventions-finding","name":"Conventions","description":"Conventions.","questions":[{"text":"How are east and west longitude, signed values and the 180th meridian handled?","kind":"definition"},{"text":"Which entry fits geographic coordinate system?","kind":"action"}]}]}]},{"id":"measure","name":"Measure","description":"Measurement.","layers":[{"id":"modern","name":"Modern","description":"Modern measurement.","findings":[{"id":"modern-finding","name":"Modern","description":"Modern.","questions":[{"text":"How do GNSS and geodetic datums determine longitude today?","kind":"measurement"},{"text":"Which references are standard?","kind":"provenance"}]}]},{"id":"historical","name":"Historical","description":"Historical measurement.","findings":[{"id":"historical-finding","name":"Historical","description":"Historical.","questions":[{"text":"How were chronometers and lunar distances used to find longitude at sea?","kind":"provenance"},{"text":"Which sources are cited?","kind":"provenance"}]}]}]},{"id":"use","name":"Use","description":"Uses.","layers":[{"id":"mapping","name":"Mapping","description":"Mapping and navigation.","findings":[{"id":"mapping-finding","name":"Mapping","description":"Mapping.","questions":[{"text":"How is longitude used in maps, charts and navigation?","kind":"provenance"},{"text":"Which entry fits navigation?","kind":"action"}]}]},{"id":"time","name":"Time","description":"Time zones.","findings":[{"id":"time-finding","name":"Time","description":"Time.","questions":[{"text":"How does longitude relate to solar time and time zones?","kind":"provenance"},{"text":"Which entry fits time zone?","kind":"action"}]}]}]},{"id":"context","name":"Context","description":"History and beyond Earth.","layers":[{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How was the longitude problem solved, from the Longitude Act to Harrison and the 1884 conference?","kind":"provenance"},{"text":"Which entry fits the history of longitude?","kind":"action"}]}]},{"id":"planets","name":"Planets","description":"Other bodies.","findings":[{"id":"planets-finding","name":"Planets","description":"Planets.","questions":[{"text":"How is longitude defined on the Moon, Mars and the celestial sphere?","kind":"provenance"},{"text":"Which entry fits planetary coordinate system?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Convert and report longitude in degrees and the stated datum.","Explain the prime meridian and the history of measuring longitude.","Use coordinates to navigate within the area it is authorized to operate."],"mustNot":["Mix datums or formats in a way that misplaces a position.","Swap latitude and longitude or drop the sign of east and west.","Publish the precise position of a person, home or protected site without consent or need."],"requiresHuman":["Using a position for search and rescue or emergency dispatch."]},"ethics":{"considerations":["Wrong coordinates can send rescuers or vehicles to the wrong place.","Precise positions reveal where people live and where rare species or sites are."],"affectedParties":["Navigators and travellers","People whose location is shared","Emergency responders"]},"owners":{"steward":"Nobody owns the concept; geodetic agencies maintain the reference frames.","roles":[],"masterSystems":[]},"relations":[{"target":"Q107715","type":"parent","note":"registry parent class"},{"target":"physical quantity","type":"related","note":"in registry terms"},{"target":"latitude","type":"related","note":"to locate points"},{"target":"prime meridian","type":"related","note":"at Greenwich"},{"target":"time zone","type":"related","note":"in principle"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.longitude","Wikidata: Q36477 (https://www.wikidata.org/wiki/Q36477)"]},"properties":{"applicability":"not-applicable","items":["range: 0-180 degrees east and west","prime meridian: Greenwich, IERS reference meridian note","one degree at the equator: about 111 km","Longitude Act: 1714 year - British prize"]},"recognition":{"applicability":"optional","items":["East-west angular position from the prime meridian","East and west longitude, 0 to 180 degrees","Latitude is north-south; local time depends on longitude; celestial longitude is on the sky","Not a visible object; meridian lines on a globe."]},"capabilities":{"applicability":"required","items":["explain definition and conventions","relay measurement and history","describe uses","distinguish related quantities"]},"hazards":{"applicability":"required","items":["Sign and hemisphere confusion","Datum differences between historical and modern longitude","Registry alias ZGD is an unclear code"]},"interfaces":{"applicability":"required","items":["IERS reference meridian and WGS 84","ISO 6709 for coordinate representation","International Meridian Conference of 1884"]},"context":{"applicability":"required","items":["Locating east-west position.","east longitude","west longitude","geodetic longitude in modern datums","historical longitude from chronometers and lunar distances","celestial and planetographic longitude"]}},"sources":[{"title":"Wikidata item Q36477: longitude","url":"https://www.wikidata.org/wiki/Q36477","note":"identity and sense of the item"},{"title":"Wikipedia: Longitude","url":"https://en.wikipedia.org/wiki/Longitude","note":"general description of the item"}],"openQuestions":["Should prime meridian and the history of longitude be separate primary entries?","How should geodesy sources be linked?","The registry alias ZGD should be reviewed"],"resources":{"spec":"/models/things/publications/thing-q36477/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q36477/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-13T13:11:03Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:51:59+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}