prime meridian
Longitude's starting line
The prime meridian is the line of longitude designated as zero degrees, from which all other longitudes are measured east or west.
By international convention since 1884, this line passes through Greenwich, England.
The prime meridian and the International Date Line together divide the Earth into Eastern and Western Hemispheres.
East-west angular distance
- latitudeGeographic or personal freedom
- equatorMidpoint circle of rotation
- hemisphereHalf of a ball
- coordinatesLocation-specifying number pairs
cartography · map · globe · geodesy · reference line · Eastern Hemisphere · Western Hemisphere · International Date Line
Astronomy institution at Greenwich
- EnglandLargest British country
- GMTGlobal time baseline
- UTCUniversal time standard
- observatoryFacility for celestial study
London · chronometer · navigation · telescope · timekeeping · maritime · British Empire · standardization
Global time baseline
- UTCUniversal time standard
- timezoneLongitudinal time region
- solar timeTimekeeping by sun position
- mean timeIntervening time span
standard time · time zones · noon · local time · world time
Starting point or source
- baselineStandard for comparison
- reference pointStandard for comparison
- starting pointPlace of commencement
- divisionSplitting into parts
longitude
East-west angular distance
- latitudeGeographic or personal freedom
- equatorMidpoint circle of rotation
- hemisphereHalf of a ball
coordinates · cartography · map · globe · geodesy · reference line · Eastern Hemisphere · Western Hemisphere · International Date Line · parallels
Royal Observatory
Astronomy institution at Greenwich
observatory · London · chronometer · navigation · telescope · timekeeping · maritime · British Empire · standardization · 1884
GMT
Global time baseline
- UTCUniversal time standard
- timezoneLongitudinal time region
- solar timeTimekeeping by sun position
mean time · standard time · time zones · noon · local time · world time
origin
Starting point or source
- baselineStandard for comparison
- reference pointStandard for comparison
- starting pointPlace of commencement
division · east-west · coordinate system · demarcation · boundary
- Earthearth, Earth, globe, continent, axis
- geographycontinents, continent, oceans, countries, country
- hemisphereshemisphere, Northern Hemisphere, Southern Hemisphere, Eastern Hemisphere, Western Hemisphere
- map featurescompass, compass rose, legend, scale, scale bar
- Map Termslatitude, longitude, equator, parallel, graticule
- 20th century world mapsatlas, globe, world atlas, map legend, map key