LEARN ABOUT LONGITUDE AND LATITUDE
Move your mouse over the image to see latitude and longitude
Latitude and longitude come from simple spherical geometry.
WHAT IS LATITUDE?
A line of latitude or Line of Parallel is an imaginary line around the earth that runs parallel to the
equator. It shows in degrees (º) how far north or south a place is. The latitude of 0 degrees is on the
equator an imaginary line on the earth's surface. The equator divides the earth into the Northern
Hemisphere and Southern Hemisphere (from Greek hemi = half). In the Galapagos Islands, the equator line
passes through the northern part of Isabela, the biggest island in the archipelago. Look at a map of the world to
see the other places though which the equator passes. The angle between the equator and the poles is 90 degrees so
the Poles are at 90 degrees north or south. The farthest north or south you can go is 90 degrees, which puts you on
the North or South Pole.
WHAT IS LONGITUDE?
A line of Longitude shows distance in degrees you are east or west from a special line that joins the north
and South Pole. The world turns west to east (anticlockwise from above). So defining a 0 line is more arbitrary
than for latitude hence, the Greenwich Meridian and Greenwich Mean Time had to be created. To make lines of
longitude, slice through the earth at the equator where you'll make a horizontal circle. Divide the edge of
this horizontal circle into two sets of 180 degrees (East or West). The 0 degree line passes through Greenwich to
make the Greenwich Meridian. Next, make imaginary lines north and south from the equator that they converge on each
pole. Now you have the meridians or lines of Longitude.
In the 18th century England was the world's greatest sea power and had a large Navy. The country had the most
technologically advanced observatory in the world. Observatories are special laboratories for studying meteorology
and astronomy. When maritime nations gathered to choose the special north-south line they decided the line should
run though the main telescope of the Royal Greenwich Observatory. Ever since that meeting, mapmakers have the
placed the 0 degree Longitude Meridian running through Greenwich, England in London. This also explains why all the
world's time zones are relative to Greenwich Mean Time (GMT).
"These tested Our Horizon
As Birds before achieving
Emily Dickinson These tested Our Horizon 1955