45o astrolabe

A mechanical device, predecessor to the sextant, whereby mariners determined the time of day by the Sun, of the night by the stars, and the height and depth of mountains and ...

subtropical

Earth science; Mapping science

Relating to the warmest region of the Temperate Zones that border on the Torrid Zone.

sky

Earth science; Mapping science

The region above and beyond the Earth, as it is seen looking up from the ground. Sky looks blue during the day and dark at night.

South Pole

Earth science; Mapping science

The most southern point of the Earth. The South Pole is the southern end of the axis on which the Earth rotates.

prime meridian

Earth science; Mapping science

The line of longitude that passes through the town of Greenwich, England, and that measures 0 degree. It is the line from which other longitude lines are measured.

planet

Earth science; Mapping science

A celestial body revolving around a sun in a nearly circular orbit. This definition excludes comets, which have highly elliptical orbits. However, it may also exclude some of ...

area of error

Earth science; Mapping science

A figure within which the true location of a point whose location has been determined by measurement is believed to lie, with stated degree of probability.