Latitude ( or ). It is measured in degrees, minutes and seconds or decimal degrees, north or south of the equator. The precise measurement of latitude requires an understanding of the gravitational field of the Earth, either to set up theodolites or to determine GPS satellite orbits. The study of the figure of the Earth together with its gravitational field is the science of geodesy. This article relates to coordinate systems for the Earth: it may be extended to cover the Moon, planets and other celestial objects by a simple change of nomenclature. The graticule is formed by the lines of
The Blood Line anything in the way that, say, some of the sacrifices in "Children of Earth" did.' He also criticised the effect of the cliffhanger, saying 'so it turns out that this huge world-changing event was just a "trial run" for an even bigger plan on the part of the bad guys? Does anyone (other than Davies) think that what the series needs is to get even bigger?' The Blood Line "The Blood Line" is the tenth and final episode of "", the fourth series of the British science fiction television series "Torchwood". It was first broadcast in the United States on