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What is a map What is a map projection?projection?

A way of showing the A way of showing the curved surface of the earth curved surface of the earth

on a flat map.on a flat map.

Homolosine ProjectionHomolosine Projection

Robinson ProjectionRobinson Projection

Gall-Peters MapGall-Peters Map

Planar ProjectionPlanar Projection

Conic ProjectionConic Projection

Cylinder ProjectionCylinder Projection

Why are there so many Why are there so many different types of maps?different types of maps?

Each map has Each map has strengths and strengths and weaknesses.weaknesses.

What causes each map’s strengths What causes each map’s strengths and weaknesses?and weaknesses?

One cannot take a 3 One cannot take a 3 dimensional object and dimensional object and make it 2 dimensional make it 2 dimensional

withoutwithout

Distortion

Planar ProjectionsPlanar Projections

Planar/AzimuthalPlanar/Azimuthal A planar projection is also called an A planar projection is also called an

azimuhtal projection. It distorts size and azimuhtal projection. It distorts size and shape.shape.

Azimuthal projection shows the earth Azimuthal projection shows the earth centered in such a way that a straight line centered in such a way that a straight line coming from the center to any other point coming from the center to any other point represents the shortest distance.represents the shortest distance.

These are often used in air navigation.These are often used in air navigation.

Conical ProjectionsConical Projections

ConicalConical A conic projection comes from the A conic projection comes from the

idea of placing a cone over part of idea of placing a cone over part of the globe. the globe.

This projection shows shape fairly This projection shows shape fairly accurately, but it distorts accurately, but it distorts landmasses at the edges of the landmasses at the edges of the map.map.

Cylindrical/MercatorCylindrical/Mercator

Mercator/CylindricalMercator/Cylindrical A mercator projection comes from the idea A mercator projection comes from the idea

of wrapping a piece of paper around a globe of wrapping a piece of paper around a globe to make a cylinder. Such a map shows to make a cylinder. Such a map shows shapes fairly accurately but not size or shapes fairly accurately but not size or distance.distance.

Areas away from the equator are distorted. Areas away from the equator are distorted. Greenland and Alaska will appear much Greenland and Alaska will appear much larger than they are on a globe.larger than they are on a globe.

These are primarily used for sea travel.These are primarily used for sea travel.

RobinsonRobinson

RobinsonRobinson A A RobinsonRobinson projection is projection is

commonly used in textbooks. It commonly used in textbooks. It shows the entire earth with nearly shows the entire earth with nearly the true sizes and shapes of the the true sizes and shapes of the continents and oceans. continents and oceans.

The shapes of the landforms near The shapes of the landforms near the poles appear flatthe poles appear flat. .

Gall-PetersGall-Peters

Gall-PetersGall-Peters

On the Gall-Peters projection, the sizes of On the Gall-Peters projection, the sizes of landmasses are accurate. In particular landmasses are accurate. In particular South America, Africa and Southeast Asia South America, Africa and Southeast Asia are shown in their correct size relationship are shown in their correct size relationship to North America and Europe.to North America and Europe.

Their shapes, however, are greatly distorted Their shapes, however, are greatly distorted and distances are inaccurate.and distances are inaccurate.

The important thing to The important thing to remember…….remember…….All maps have All maps have

strengths and strengths and weaknesses.weaknesses.

All Have Distortion!!All Have Distortion!!

Heavyweight Champion Heavyweight Champion RobinsonRobinson

vs.vs.

Contender Contender

Gall-PetersGall-Petershttp://www.youtube.com/watch?v=n8zBC2dvERM