What is a map projection? A way of showing the curved surface of the earth on a flat map.

Why are there so many different types of maps? Each map has strengths and weaknesses. Each map has strengths and weaknesses.

Cartographers Cartographers (Mapmakers) have had challenges making maps to accurately show size, shapes and distance of our earth.

What causes each map’s strengths and weaknesses? One cannot take a 3 dimensional object and make it 2 dimensional without One cannot take a 3 dimensional object and make it 2 dimensional without Distortion

Planar Projections

Planar/Azimuthal  A planar projection is also called an azimuhtal projection. It distorts size and shape.  Azimuthal projection shows the earth centered in such a way that a straight line coming from the center to any other point represents the shortest distance.  These are often used in air navigation.

Conical Projections

Conical  A conic projection comes from the idea of placing a cone over part of the globe.  This projection shows shape fairly accurately, but it distorts landmasses at the edges of the map.

Cylindrical/Mercator

Cylindrical/Mercator  A mercator projection comes from the idea of wrapping a piece of paper around a globe to make a cylinder. Such a map shows shapes fairly accurately but not size or distance.  Areas away from the equator are distorted. Greenland and Alaska will appear much larger than they are on a globe.  These are primarily used for sea travel.

Robinson

Robinson  A Robinson projection is commonly used in textbooks. It shows the entire earth with nearly the true sizes and shapes of the continents and oceans.  The shapes of the landforms near the poles appear flat.

Gall-Peters

Gall-Peters  On the Gall-Peters projection, the sizes of landmasses are accurate. In particular South America, Africa and Southeast Asia are shown in their correct size relationship to North America and Europe.  Their shapes, however, are greatly distorted and distances are inaccurate.

Comparing Projections

The World according to the United States

The important thing to remember…….  All maps have strengths and weaknesses.  All Have Distortion!!