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Mapping Our World Standard 1. h: Read and interpret topographic and geologic maps.
Understanding Maps • In order to find locations on Earth, cartographers have created an imaginary grid of parallel lines and vertical lines. • The equator is an imaginary line that circles Earth halfway between the north and south poles. • This separates Earth into two hemispheres: 1. Northern Hemisphere 2. Southern Hemisphere
Latitude • Imaginary lines that run parallel to the equator • The distance in degrees North or South of the equator Measured from 0° at the equator to 90° at the poles
• Locations north of the equator are referred to by degrees north latitude (N). • Locations south of the equator are referred to by degrees south latitude (S). South Latitude is located South of the Equator
Degrees of Latitude – Each degree of latitude is equivalent to about 111 km on Earth’s surface. – To locate positions on Earth more precisely, cartographers break down degrees of latitude into 60 smaller units, called minutes (´). – A minute of latitude can be further divided into 60 seconds (´´). – Longitude is also divided into degrees, minutes, and seconds.
Longitude • Also known as meridians. • Distance in degrees east or west of the prime meridian. The prime meridian, representing 0° longitude, is the reference point for longitude.
• The Prime Meridian divides Earth into East and West Hemispheres
(Runs through Greenwich, England) • Points west of the prime meridian are numbered from 0° to 180° west longitude (W). • Points east of the prime meridian are numbered from 0° to 180° east longitude (E).
• Longitude lines are not parallel; they are large semicircles that extend vertically from pole to pole. • Distances covered by degrees of longitude vary with location. • One degree of longitude varies from about 111 km at the equator to essentially the distance covered by a point at the poles.
Locating Places with Coordinates – Both latitude and longitude are needed to precisely locate positions on Earth. – For example, the location of New Orleans is 29° 57´N, 90° 04´W. – Latitude always is written first.