CHAPTER 2 MAPPING OUR WORLD

Latitude & Longitude Cartography – Science of mapmaking. Cartographers use an imaginary grid of parallel lines and vertical lines to locate points on Earth.

Latitude & Longitude The equator circles Earth halfway between the north and south poles. Above equator = Northern Hemisphere Below equator = Southern Hemisphere

LATITUDE Lines of latitude are lines running parallel to the equator. Latitude is the distance in degrees north or south of the equator.

LONGITUDE Distance in degrees east or west of the prime meridian. Prime Meridian: Representing 0° Longitude, it is the reference point for longitude.

LONGITUDE Points west of Prime Meridian are numbered 0°-180° W Longitude. Points east of Prime Meridian are numbered 0°-180° E Longitude.

LONGITUDE To locate positions more precisely, latitude and longitude are broken down into minutes and seconds

Locating With Coordinates Both latitude & longitude are needed to precisely locate positions on earth. Latitude comes first, then longitude Ex: New Orleans = 29°57’ N, 90°04’ W

TIME ZONES Because Earth takes 24 hours to rotate once on its axis, it is divided into 24 time zones. Each time zone represents a different hour.

TIME ZONES Each time zone is 15° wide. The US has six different time zones.

International Date Line International Date Line: 180° Meridian serves as transition for calendar days. Traveling west = Advanced one day Traveling east = Move back one day

TYPES OF MAPS

1. Mercator Projections Has parallel lines of latitude and longitude. Shapes of landmasses are correct, but their areas are distorted.

2. Conic Projections A map made by projecting points and lines from a globe onto a cone. Distortion is evident near the top and bottom of the projection

3. Gnomonic Projections Map made by projecting points and lines from a globe onto a piece of paper that touches the globe at a single point. Distort direction and distance between landmasses.

4. Topographic Maps Maps showing the elevation of hills and valleys. Contour lines: Connects points of equal elevation. Contour Interval: Difference in elevation between two side-by-side contour lines. Index Contours: Contour lines marked by their true elevation

Map Legends Explains or depicts what the symbols mean on a topographic map. Map Scales: Ratio between the distances on a map and actual distances on Earth’s surface.

Remote Sensing Process of collecting data about Earth far above Earth’s surface.

Electromagnetic Spectrum Satellites detect different wavelengths of energy reflected or emitted from Earth’s surface. Ex: visible light, X rays, ultraviolet waves, infrared waves, radio waves, and microwaves.

Electromagnetic Spectrum Frequency: Number of waves that pass a point each second.

LANDSAT SATELLITES Receives reflected wavelengths of energy emitted by Earth’s surface. Topex/Poseidon Satellite: Uses radar to map features on the ocean floor.