Linked from

The 41 pages that link to Longitude, each with the reason it gives.

• GeodesyRelated: Longitude locates points around Earth within a geodetic coordinate system.

• Treaty of TordesillasNarrower topic: The boundary depended on locating a line at a specified westward distance.

• Dead reckoningRelated: Together with latitude, it specifies the location advanced by the estimate.

• LatitudeRelated: Together, latitude and longitude locate positions on Earth.

• Map projectionRelated: Projection formulas transform longitude as well as latitude into map coordinates.

• Geographic coordinate systemRelated: It supplies the east–west component of the system’s usual coordinate pair.

• EquatorRelated: Together, latitude and longitude specify positions on Earth’s coordinate grid.

• Marine chronometerRelated: Understanding the quantity to be found clarifies why accurate time matters.

• Degree (angle)Related: Its positions are conventionally reported in degrees.

• Mechanical clockRelated: Comparing local time with a reference clock makes longitude measurable.

• EratosthenesRelated: His mapping work addressed the east–west positions of places in the known world.

• Marine navigationRelated: Together with latitude, it identifies a position on a chart.

• Maritime navigationRelated: Longitude completes the geographic coordinate pair used to describe position.

• Greenwich Mean TimeRelated: Longitude connects local solar time to Greenwich’s reference meridian.

• SunriseRelated: Longitude shifts local sunrise time relative to other places in a time zone.

• Solar timeRelated: Different longitudes experience solar noon at different instants.

• CircumnavigationRelated: A route that changes longitude through a full 360 degrees can establish an eastward or westward circuit.

• Hour angleCompared with: Like hour angle, longitude is angular, but it locates places on Earth rather than objects relative to a local meridian.

• Gerardus MercatorRelated: The projection represents meridians as parallel vertical lines.

• MeridianNarrower topic: A meridian is one line in the coordinate system that longitude measures.

• Prime meridianNarrower topic: The prime meridian supplies the zero point for measuring it.

• Rhumb lineRelated: Meridians are the coordinate lines crossed at the rhumb line's fixed angle.

• World mapRelated: Longitude lines provide the second coordinate needed to place locations on a world map.

• Lunar distance methodNarrower topic: The method’s final result is the observer’s longitude from a time difference.

• Treaty of ZaragozaNarrower topic: Determining longitude at sea was difficult, making the treaty’s global boundary hard to locate precisely.

• Nevil MaskelyneNarrower topic: Solving longitude at sea was the practical problem that shaped Maskelyne's work.

• Astronomical tablesRelated: Reliable lunar and planetary tables helped make longitude estimable from celestial observations.

• Ancient Greek geographyRelated: Greek attempts to compare east–west distances exposed the limits of ancient location-making.

• William BaffinRelated: Reliable longitude remained difficult to determine at sea in Baffin’s era.

• 180th meridianNarrower topic: The 180th meridian is one line of constant longitude.

• Eastern HemisphereNarrower topic: Longitude determines which side of the prime meridian a place occupies.

• Azimuthal equidistant projectionRelated: The central point is specified partly by its longitude.

• History of geographyRelated: Reliable longitude measurement transformed navigation and the global positioning of places.

• History of navigationRelated: Reliable longitude at sea required accurate timekeeping as well as observation.

• History of timekeeping devicesRelated: Comparing local solar time with a reference clock allows longitude to be calculated.

• ChronometryRelated: Comparing local solar time with a reference time reveals longitude.

• Circle of latitudeRelated: Longitude locates positions along a circle of latitude.

• East (direction)Related: Eastward longitude records position relative to the Greenwich meridian or another datum.

• Guillaume DelisleRelated: Determining longitude accurately was a central obstacle for the world maps Delisle sought to improve.

• Hemispheres of EarthNarrower topic: Longitude locates places relative to the meridians used for the east–west division.

• Zonal and meridional flowRelated: Meridional motion follows lines of constant longitude.