Latitude & Longitude

Coordinate System Systems used to define positions (locations) of points on Earth or in space Use latitude and longitude

Latitude Distance in degrees, north or south of the equator 90°N= North Pole 0⁰= Equator 90°S= South Pole Lines of latitude are also called parallels (run parallel to the equator) Latitude is measured from the equator- *when measuring start here* Maximum degrees= 90 °N or 90 °S

Latitude In the northern hemisphere, determine latitude by measuring the altitude of Polaris (North Star) above the horizon (in degrees). Measure UP from the horizon In the southern hemisphere, altitude of Polaris is the same as the person’s latitude In the southern hem, people don’t use Polaris- Use “south star” Sigmas Octanisis

Latitude Realize someday both north and south stars will change due to Earth’s a slight wobble in Earth’s rotation Slowly the earth’s rotational axis is changing, so the north star will too (26,000 yrs)

Longitude How do we get this?... Based on sun’s apparent motion in the sky Earth rotates 15°/hr How do we get this?... Earth rotates once in 24 hours That means 360° rotates in 24 hrs = 15°/hr Rotates counter-clockwise from west to east

Longitude Longitude is measured from east to west of the prime meridian The Prime Meridian passes through Greenwich, England (0° Longitude) Longitude is measured from the prime meridian- * when measuring start here*   As you travel east or west, longitude increases until maximum degrees of 180°E or 180°W

Longitude Greenwich Mean Time (GMT)- time it is in Greenwich, England Solar Time- noon- sun is highest in the sky- at YOUR location

Longitude and Time If it’s noon at your location and you know the time in Greenwich, you can calculate longitude (Remember that the earth rotates 15°/hr) It’s 2:00 pm in Greenwich (GMT) when it’s noon at your location (12:00 pm) Time difference= 2 hr 2 hours x 15°/hr= 30° Your longitude= 30°W

Longitude & Time If it is NOON your time and GMT= PM, you are WEST of the Prime Meridian If it is NOON your time and GMT=AM, you are EAST of the Prime Meridian

Writing Latitude and Longitude Requires both DEGREES and DIRECTION (unless 0°) Latitude= North or South Longitude= East or West

Writing Latitude and Longitude Latitude listed FIRST, then longitude Ex. 42°N, 31°E 88°S, 178°W

Writing Latitude and Longitude Latitude and longitude can also be further broken down into MINUTES (‘)- even more precise There are 60 minutes in one degree Ex. Latitude= 42° 15’ N Longitude= 31° 56’ E