MAPS Chapter 3
3.1 Finding Locations on the Earth • Distinguish between latitude and longitude. • Explain how latitude and longitude can be used to locate places on the earth. • Explain how a magnetic compass can be used to find directions on the earth.
Latitude: 3.1 Finding Locations on the Earth • The distance in degrees north and south of the equator • Measured by parallels which are imaginary lines that circle the world. • The largest parallel is the equator • One degree of latitude is equal to 70 mi or 112 km.
Longitude: 3.1 Finding Locations on the Earth • The distance in degrees east or west of the prime meridian • Measured by meridians which are lines that runs from the north to the south poles. • The Prime Meridian runs through Greenwich, England, and is 0o longitude
Longitude • Locations east of the prime meridian have longitudes between 0◦ and 180◦ E • Locations west of the prime meridian have longitudes between 0◦ and 180◦ W
Longitude • The distance covered by a degree of longitude depends on where the degree is measured. The distance measured by a degree of longitude decreases as you move from the equator to the poles. • At 60 ◦ N one degree = 55 km • At 80 ◦ N one degree = 20 km
3.1 Finding Locations on the Earth Great Circles: • Divide the globe into halves • The shortest distance between two points on a globe • Used to plan air and sea routes
3.1 Finding Locations on the Earth Great Circles: • Divides the globe into halves • The shortest distance between two points on a globe • Used to plan air and sea routes
Finding Direction • Geomagnetic poles- the points on the earth’s surface just above the poles of the imaginary magnet inside the earth. A compass needle points to the geomagnetic North Pole • The Geographic North pole is located in a different place than the Geomagnetic pole. • Magnetic declination is the angle between the direction of the geographic pole and the direction in which the compass needle points • Boston Massachusetts-declination is 15 W of true north • San Antonio Texas- declination is 15 E of true north
3.2 Mapping the Earth’s Surface • Describe the characteristics and uses of three types of map projections. • Define scale, and explain how scale can be used to find distance on a map.
MAP PROJECTIONS, LOCATIONS, & SCALES real thing model ModelRepresentation of an object or idea Map Model of the earth’s surface on a sheet of paper
HOW DO WE MAKE A MAP WHEN THE EARTH IS ROUND?? Map Projection Transferring the curved surface of the earth onto a flat map 3 Major Types Mercator, Gnomonic, Conic
MAP PROJECTIONS • MERCATOR: • Shows the whole world • Shows true direction by straight lines. • Distortion is greatest at the poles.
MAP PROJECTIONS GNOMONIC: A projection made as if a sheet of paper were laid on one point on earth’s surface. Shows shortest route by straight line. Useful in plotting routes for air travel as it helps navigators find a great circle route. London to Tokyo
MAP PROJECTIONS CONIC: Nearly correct in all respects; this means latitude and longitude lines have a slight curve Best for showing the shapes of land masses Most accurate for making topographic maps
3.3 Topographic Maps • Explain how elevation and topography can be shown on a map. • Interpret a topographic map.
Important Features On A Topographic Map • Scale = shows the ratio of distance on the map to distance on the earth • Key / Legend = shows you what the symbols are on a map • Directional Compass = shows true north • Mileage Chart = shows common places on a map and how far they are apart
Important Features On A Topographic Map • Elevation is shown by contour lines. • Contour Interval = the difference in the elevation between adjacent contour lines. • Depression Contours = contours that show a lower area on a map; shown with closed contour lines that contain hachure marks on the inside.
Important Features On A Topographic Map • Bench Mark/Spot Elevation = place on a topographic map that shows exact elevation above sea level • Magnetic Declination = is the difference in degrees between magnetic north and true north. • Gradient = change in elevation in feet divided by the distance in miles
MODERN METHODS OF MAPMAKING • Remote sensing • Computer imaging • Use of computer-drawn maps and images