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Home , Latitude, Map projection

194

There are several ways of finding places on a . 65˚WA 64˚WBCD 63˚W 62˚W 61˚W This uses three different methods: 47˚ 47˚ • letters and numbers around the edge of the map N Tignish N N • lines of and drawn on the map o PRINCE EDWARD r • the military grid system (see page 199) for Canadian t ISLAND h topographic East 2 u Point 2 m b Summerside Margaree Forks e Souris 1 LETTERS AND NUMBERS r Charlottetown l a n Moncton d Murray 46˚ S Harbour Cape 46˚ N t 1. Find the name of the place in the gazetteer. r George N Dorchester a Amherst i t St 2. Find the page number and reference (e.g., page 2, F2). George’s Bay 3. Go to the correct page in the atlas. Antigonish Alma 4. Find F in the border below the map, and find 2 on the side equid Mounta 1 Cob ins 1 of the map. Advocate Truro 5. Follow the letter up and follow the number across to find the Harbour correct square (F2). Sherbrooke Kentville Upper Musquodoboit 6. Locate the place by searching the square. 45˚ 45˚ N N Look at the map of Atlantic Canada. Charlottetown is located at 65˚WABCD 64˚W 63˚W 62˚W 61˚W B2, Truro is located at B1, and Moncton is located at A2. 2 LATITUDE 3 LONGITUDE 4 FINDING PLACES

Latitude is , measured in degrees, Longitude is distance, measured in When lines of latitude and longitude are and of the . Lines of degrees, east and of the drawn on a map, they form a grid, which latitude circle the in an east-west . Lines of longitude join the poles looks like a pattern of squares. This direction. The distance between lines of in a north-south direction. Because the pattern is used to find places on a map. latitude is always the same; therefore, they lines join the poles, they are always the Latitude is always stated before longitude are also known as parallels of latitude. same length, but are farthest apart at the (e.g., 42°N, 78°W). Because the circumference of gets equator and closest together at the poles. smaller toward the poles, the lines of These lines are also called meridians of latitude are shorter nearer the poles. longitude.

North Pole (90°N) (90°N) 661/2˚ N North Pole (90°N)

75˚N A ) rc 1 N tic Circle (66 /2˚ 1 60˚N 23 /2˚ N

6 0 ˚W ˚E 45˚N 60 3 0˚W 30˚E 30˚N 0˚

T 1 ) ropic of Cancer (23 /2˚ N 60˚W 60˚E 15˚N 30˚W 30˚E Eq °) 1 uator (0 23 /2˚ S 0˚ Greenwich Meridian

15˚S Tr 1 S) opic of Capricorn (23 /2˚

South Pole (90˚S) (90˚S) South Pole (90˚S)

All lines of latitude have numbers Longitude begins along the Prime On the map of Atlantic Canada (above), between 0° and 90° and a direction, Meridian, or Greenwich Meridian, at 0°, in Murray Harbour is directly on a line of either north or south of the equator. The London, England. On the opposite side of latitude — representing 46°N. Similarly, equator is at 0° latitude. It divides Earth Earth is the 180° meridian, which is the Antigonish is directly on a line of into two halves: the Northern and International Date Line. These two lines longitude — representing 62°W. Southern Hemispheres. The North Pole is can be used to divide Earth into two Other places, not exactly on lines, use at 90° north and the South Pole is at 90° halves: the and the subdivisions of degrees called minutes. south. The “tilt” of Earth has given . To the west of the There are 60 minutes in a . Truro particular importance to some lines of Prime Meridian are Canada, the United is located almost halfway between 45°N latitude . They include: States, and Brazil; to the east of the Prime and 46°N and about one quarter of the • the at 661/2° north Meridian are Germany, India, and . distance between the lines 63°W and • the at 661/2° south All lines of longitude have numbers 64°W longitude. Its latitude and longitude • the at 231/2° north between 0° and 180° and a direction, would be 45° 25’N, and 63° 15’W. • the at 231/2° south either east or west of the prime meridian. MAP PROJECTIONS 195

Since Earth is a and maps are flat, map makers (cartographers) have invented different ways of drawing the round of Earth on a flat piece of paper. These methods are called map projections.

There are many different types of map projections, but none of them can perfectly match the sphere of Earth. Every map must “stretch” or “squash” the round surface to make it fit onto a flat piece of paper. As a result, no can correctly show all four aspects of a map—, area, direction, and distance—at the same time. In drawing any ONE of these four aspects accurately, the other three become distorted or inaccurate. Each map projection has advantages and disadvantages.

1 CYLINDRICAL PROJECTIONS 2 CONIC PROJECTIONS 3 AZIMUTHAL PROJECTIONS

Cylindrical projections are constructed by Conic projections are constructed by Azimuthal projections are constructed by projecting the surface of the globe or projecting the surface of a globe or projecting the surface of the globe or sphere (Earth) onto a that just sphere (Earth) onto a that just sphere (Earth) onto a flat surface that touches the outside edges of that globe. touches the outside edges of that globe. touches the globe at one point only. Two examples of cylindrical projections Examples of conic projections are Albers Some examples of azimuthal projections are Mercator and Times. Equal Area Conic and Chamberlin are Lambert Azimuthal Equal Area and Trimetric. Polar Stereographic. Mercator (see pages 154-155 for an Albers Equal Area Conic (see pages Lambert Azimuthal Equal Area (see pages example of this projection) 136-137 for an example of this projection) 158-159 for an example of this projection)

The Mercator cylindrical projection is a useful projection for near the Conic projections are best suited for areas equator and to about 15 degrees north between 30° and 60° north and south of or south of the equator, where the equator when the east-west distance Lambert’s projection is useful for areas of shape is minimal. The projection is is greater than the north-south distance that have similar east-west and useful for , since directions are (such as ). The meridians are north-south such as Australia. plotted as straight lines. straight and spaced at equal intervals. Times (see pages 80-81 for an example Chamberlin Trimetric (see page 108 Polar Stereographic (see page 167 for of this projection) for an example of this projection) an example of this projection)

The Times projection is similar to the , but the meridians of Chamberlin Trimetric is an equidistant This projection is a good choice for showing longitude are slightly curved. The Times projection. It is used to show areas with travel routes from a central point because projection is most accurate halfway greater north-south extent than east- points on the map are in constant relative between the poles at 45°N and 45°S. west extent (such as North America). position and distance from the centre.