When did they start to use longitude and latitude to locate things?
(Posted by: Sol on 2012-03-06 18:28:13)
Google is always the answer.
Long long ago when they started using ships to cross the Oceans. Britain being in the forefront of navigation to serve the needs of ships ' captains, established an observatory at Greenwich, outside London city. By then compass has become an essential navigational aid (tool) on an ocean-going vessel. When they started to take the sightings of a particular star called 'Polaris ' which is a pointer to the north direction, they discovered that the elevation (above the horizon) of that star is the latitude of the place. By a series of calculation to determine how far west or east of Greenwich (mostly by measuring the transit of star that has a 'culmination ' based on the calender date) and comparing with what would be such a similar scene at Greenwich they could establish the longitude. Then, telegraph was invented making messages possible to be sent instantaneously. So they could know what time it was at Greenwich & by measuring the time difference & factoring in the "15°/ hour " they were able to pinpoint on what longitude they were compared to Greenwich that they established as the reference (0°).