Symptoms include: 1  Itching. 2  Significant tearing and production of thick mucus. 3  The feeling of having something in the eye (foreign body sensation) 4  Aversion to light (photophobia)
Geographic coordinate system. Longitude lines are perpendicular to and latitude lines are parallel to the equator. A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are often chosen such that one of the numbers represents a vertical position, and two or three of the numbers represent a horizontal position.
The equator is zero degrees, the North Pole is 90 degrees north, and the South Pole is 90 degrees south, and in between is in between. Parallels, otherwise known as latitude lines, are lines that run across the Earth from east to west at a constant latitude. Everywhere on a parallel must have the same latitude. Your latitude can be calculated by measuring the angle of the sun. At the middle of the day on the equinox (when day and night are the same length) the angle of the sun below an upright line (a line straight up above your head) tells you your latitude.