Map Projections …is about presenting the round Earth on a flat surface.Map Projections: Vermeer’s Cartographer

What is a map projection? A projection is a way to make a flat representation of the Earth

The only accurate representation of the earth is a globe. Only a globe preserves the map qualities of area, shape, direction, and distance.

Why are all map projections distorted? All map projections must distort size, shape, distance, or direction. Watch the following video to find out why: http://goo.gl/oxC3v

Why do we use maps vs. globes? -Practical -Technology is making maps less practical, but their images will always be used.

Types of Map Projections There are three main types of map projections Cylindrical/Mercator Conic Plane/Planar/Polar/Azimuthal

For Mercator projections, please know the following: visual recognition accuracy Distortions uses

Mercator/Cylindrical Projection

Visual Recogintion At what angle to lines of latitude and longitude intersect on a cylindrical projection?

Accuracy / Distortions Compare the size of landmasses on the cylindrical projection on the left with the Robinson projection on the right to answer the following questions. Which landmasses appear much larger on the cylindrical projection than they actually are? Which landmasses on the cylindrical projection appear to be accurate in size?

Accuracy A C D B What direction would you travel to get from ‘A’ to ‘B’? What direction would you travel to get from ‘C’ to ‘D’? True Compass Rose!

Video of cylindrical/mercator projection http://goo.gl/AE5bR

For Conic projections, please know the following: visual recognition accuracy uses

Conic Projection

Visual Recognition

Watch this: http://goo.gl/rJKp4 Answer these: What visual clue is covered that will help you recognize a conic projection? (visual recognition) What parts of the world do conic projections show accurately? (accuracy/uses) Distortions?

For Planar projections, please know the following: visual recognition Uses

Plane/ Planar/ Polar/ Azimuthal Projection

Visual Recognition

Accuracy Planar projections are accurate at the point the projection touches the map

Distortions: Shape distorted at edge of projection.

Uses: Great Circle Routes The line created when you cut the globe in half connecting two points

Uses: used by pilots because great circle routes appear as straight lines.

Great Circle Route This video shows planes travelling on great circle routes to Sydney, Australia Optional http://goo.gl/lYnjw

For Gall-Peters projections, please know the following: visual recognition Why is considered politically correct?

Gall-Peters Projection Compare the Gall-Peters(left) to the cylindrical projection(right). Both projections have latitude & longitude at right angles. What differences do you see between the shape/size of landmasses. Why is the Gall-Peters projection called the “politically correct” projection? Considered the “politically correct” projection--a response to the Mercator’s greater distortion of the size of landmasses in the northern hemisphere.

For Robinson projections, please know the following: visual recognition

Robinson Projection The Robinson projection does not eliminate distortion, but it keeps the levels of distortion low over all parts of the map. How do distortion levels of a Robinson Projection compare to distortion levels in other map projections?

For Interrupted projections Ignore…..They are funky looking though!

Interrupted Projections: visual recognition

Interrupted Projections

We are used to looking at maps that are centered on the Prime Meridian.

VI. The Big Idea A. All map projections have distortions. B. Each projection has its own advantages and disadvantages depending on the purpose of the map.

Optional http://goo.gl/TG8XM Summary Video Optional http://goo.gl/TG8XM