What are lines of longitude and latitude?

Latitude and longitude are imaginary lines drawn on maps for the purpose of easily locating any place on Earth. Any place can be identified by a given set of latitude and longitude coordinates. Both are measured in degrees.
The latitude is measured as the distance in the north or south direction of the Equator. The North Pole has a latitude of 90 degrees N (north), while that of the South Pole is 90 degrees S (south). On the other hand, the longitude is measured as the distance in the east or west direction of the Prime Meridian (an imaginary line that runs from north to south and passes through Greenwich, England). The longitudes extend up to 180 degrees E (east) or 180 degrees W (west).
Do note that both the latitude and longitude are imaginary lines and present us with the means of locating any place.
One can find the latitude and longitude of any place by using a number of online links available from NASA and other websites.
Hope this helps.