Latitude & Longitude

Locate a point on Earth using latitude-longitude coordinates:

55 deg 45' N, 37 deg 37' E

Find the coordinates of a city:

Algiers coordinates

Distances

Compute the great-circle distance between points on the globe:

23.5S 46.4W to 56.8N 60.6E

Compute the distance between cities:

San Francisco to Tokyo

Compute distances between multiple cities:

Buenos Aires to Sao Paulo to La Paz to Panama

Compute the distance to the horizon:

how far can I see at 30,000 ft

calculate the line of sight to the horizon from Mount Everest

Compute the horizon distance for radio waves:

how far can radio waves propagate

calculate radio horizon at 100 m altitude

Bearings

Get information about a compass heading:

SSW

15 North

Geodetic Data

Get information about a geodetic reference ellipsoid:

GRS80

Compare multiple ellipsoids:

Airy 1830, Modified Fischer 1960

Get information about a geodetic datum:

GDA94

Compare multiple geodetic datums:

NAD27, ITRF00

Geogravity

Compute the current local gravitational field strength:

geogravity

Compute the gravitational field strength at specified coordinates:

geogravity 21.28N 157.60W

Geomagnetism

Compute the current local geomagnetic field strength:

geomagnetism

Compute the geomagnetic field strength for a given date and location:

geomagnetism Oslo on 12 Feb 2007